Optimising London public transport

This is a guide into public transport in London, with a particular focus into cost optimisation.

Using this guide
Most users will benefit from reading the Definitions and "For the tourist" sections; residents or long-term visitors should read the last section as well. This guide is written in a way that while it provides an overview of the public transport system within London, the goal is with cost optimisation in mind. This means that we focus on how travellers and residents can save money on travel, which can be considerable in a city like London, where transport can get pretty expensive. The fare system is also rather complicated and convoluted even to residents, and we try to simplify it in this article as well.

Fares referenced in this article are likely to change; we try to minimise mentioning fares as far as possible as a result. You can get prices for a journey from TfL or National Rail websites.

Note that some advanced techniques are not covered in this article, particularly those where it is likely to be useful or applicable outside London - see this page instead. For example, we do not discuss the usefulness of Eurorail, instead focusing on how it can be used within London.

The Oyster card
It is a plastic reloadable card that can be used to travel across London; this includes the Tube, buses and most National Rail services within London (and nearby suburbs). The exception is the Elizabeth Line from Iver to Reading, where such cards aren't valid.

TfL
Transport for London (TfL) is a government body responsible for most of London's transport system. Amongst others,


 * the London Underground (also called the tube). This also includes the DLR (Docklands Light Railway), which is part of the London Underground for the purposes of this article.
 * the London Overground and Elizabeth Line (while they are often treated as the same as the London Underground, they aren't; the difference will be shown later in this article).
 * the London Buses (to be more precise, it manages the bus services and controls things such as fares - private companies actually run the bus).
 * and the Oyster card scheme (explained above).

National Rail
It's the rail network in the United Kingdom, and has a substantial presence in London. It should be noted that National Rail is simply a trading name that unifies the myriad of companies that each run their own train services. In London, these include Southern, South Western Railway, Southeastern and Thameslink. You can book a train ticket for anywhere in the UK from any train company. Given TfL's influence in London, many TfL schemes work with National Rail trains in London, which we'll explain later.

We noted above that the London Overground and Elizabeth Line are different from the London Underground. The key difference is that these two are also part of National Rail, which means that National Rail schemes that would not be valid on London Underground (such as Britrail which we explain later) are valid on these two services.

Contactless
This involves paying using a contactless credit/debit card, or other options such as Apple/Google/Fitbit Pay. This method of payment can be used for all services within London, and a subset of train services near it. Other bus operators may also allow payment by contactless, but that's out of scope for this article.

The main issue is that contactless does not support discount schemes such as railcards (which we'll discuss later on); you'll need to get a paper ticket or use Oyster where permissible.

Paper ticket
Self-explanatory, this is a regular ticket on paper.

The zonal system


The zonal system is a series of regions that decide how much you pay for a trip if you use London Underground or National Rail services. In general, we have


 * Zone 1, which commonly refers to what is called Central London
 * Zones 2 - 6 - outside Central London but generally within London itself. The higher zones normally form the outskirts of London.
 * Zones 7 - 9 - generally outside London
 * Zones 10 - 16 (technically A - F, though not officially listed as such) - for specialist cases such as Gatwick Airport, Watford Junction and Shenfield. While these zones accept Oyster and contactless, they cost more. These stations are officially referred to in tube maps as "Special fares apply" from a cost point of view.
 * There are some stations (such as Luton) which accept contactless but not Oyster; such stations are generally out of scope for this article.

When you make a trip using Oyster or contactless, you will in essence be making a trip from Zone x to Zone y and be charged the corresponding fare between those zones. You can find the cost between two particular stations by going to https://tfl.gov.uk/fares/find-fares/tube-and-rail-fares/single-fare-finder, and we'll make several references to that site throughout this article.

Peak and off-peak
As the name suggests, this depends on when you enter the transport system (and crucially not exit). You'll pay a higher fare if you enter during the "peak" fare zone, which is usually


 * 6:30AM–9:30AM and 4PM–7PM, on weekdays only (public holidays are excluded) if you use Oyster on TfL or National Rail services
 * any time before 9:30AM otherwise, on weekdays only

There is a concession in that if you go to a Zone 1 station (not from) during the evening peak, your journey will be treated as off-peak. This is because most people would be making journeys in the other direction during that time.

Also the Watford Junction - Euston branch of the London Overground has a slightly different peak and off-peak policy. Specifically, your journey is off-peak if your journey in an otherwise "peak" journey is in the "wrong" direction. If you are going from Watford Junction (or an intermediate station) to Euston, this would be in the evening (and morning in the other direction).

Capping
This means that if you pay for your trip using the same Oyster/contactless card, the total fare you'll pay for a day or week will be upper-bounded, and any further trips you make will be free (unless your trip is one where capping does not apply, such as Heathrow Express). This depends on which zones you've travelled through (see above). There is a separate, lower, cap if you only use buses.

Railcards
It is a National Rail scheme that provides discounts to specific groups of people on rail travel.


 * On London, the 16-25 (and 26-30) railcard provides a 33% discount on off-peak travel (including Oyster). The Senior Railcard works the same way for those aged 60 or older.
 * The Network Railcard is not as good of an option because not only does it not work on Oyster, it has a geographical limitation within London. If you need to make many journeys within that region and are not eligible for the other railcards, it's a reasonable choice however.
 * The Family and Friends and Two Together railcards are only useful for their intended purposes (as the former requires at least one child, and the latter requires both named persons to travel together). While you can get a discounted paper travelcard (as part of a larger journey), they are not useful in London otherwise, and do not work on Oyster either.
 * The Disabled Persons railcard is one of the best options, as one gets a 33% all-day discount on Oyster (crucially this includes the peak period). The criteria for getting one are however narrow.

There are also other localised railcards (see here), but those are out of scope for this article.

It is important to note that most railcards have a lower-bound on morning peak-time travel, which means that there is a minimum fare (of about 12 pounds) if you use a railcard during that time. The exception is the Disabled Persons railcard (which doesn't have one at all), and the 16-25 railcard during July and August - advance tickets do not have this limitation either. The Senior Railcard is not valid at all during that time.

If you have an eligible railcard you’ll have to ask TfL station staff to add the discount to your Oyster card. This discount will apply for as long as the railcard is still valid.

Tourists should not normally get a railcard unless their main purpose is to travel within London (and that too for at at least a month), plan to make only one or two expensive train journeys or make use of localised rovers/rangers (see the Rail travel in Great Britain article); such users should look at the Eurorail and Britrail sections below instead.

Reaching London
So you've reached London. For now we'll assume that you've reached Heathrow; specific information for other airports follows later. There are three common ways to reach Central London from Heathrow:

You can also take a TfL bus from Heathrow. So which one would be best from a cost-optimisation point of view?
 * Heathrow Express: non-stop from Heathrow to Paddington in 15 minutes
 * Elizabeth Line: a stopping service from Heathrow to Paddington (from where trains to Reading can be sought), Abbey Wood and Shenfield
 * Piccadilly Line: the slowest of the three, with a journey from Heathrow to Leicester Square taking about 50 minutes. Continues all the way up to Cockfosters in north-east London.
 * The Heathrow Express is generally overpriced. The Elizabeth Line can do what the Heathrow Express does for a substantially cheaper price, and is included in Zone 1 - 6 daily caps (while the Heathrow Express isn't, so you would have to pay for any subsequent tube journeys you make that day). The only exception is if you have an advance ticket - while those are cheap in comparison, they are valid only for a certain day, and are not compatible with schemes such as capping.
 * The Elizabeth Line is not cheap. However, it is included in Zone 1 - 6 daily caps, and hence is reasonable if you plan to travel a lot that day (i.e, make multiple disjoint journeys), as you'll simply hit the cap and not pay any more for the day. The disjoint keyword is particularly important - this is because you pay for a journey from A to B - transfers between trains are free (this doesn't apply if you use the Heathrow Express).
 * If you plan to only make one or two disjoint tube journeys for the day, the Piccadilly Line would be the best choice, being substantially cheaper than the other options.
 * If time isn't an issue, the bus is the way to go (also see the Buses section below).

The National Rail premium
So now that you've reached London, and decide to stay at Clapham Junction for the night (after all this is from a long trip!). The next day, you decide to go to South Kensington (to see the museum for example). How do you get there? Google Maps is likely to recommend one of the below options:


 * There is a direct bus to South Kensington (bus 345/49); fair enough, but we'll look at that later
 * You can take a Southern train to London Victoria, and then take the District/Circle Line westwards to South Kensington
 * You can take a South Western Railway train to London Waterloo, and then (using one of the many permutations - doesn't matter) use the London Underground system to reach South Kensington station
 * You can take the London Overground train to West Brompton, and then take the District Line to South Kensington

On the surface, the three options look similar according to the zonal system - you take a train from Zone 2 to Zone 1. However, most people are unlikely to notice that this isn't the case, and will get screwed in the price. According to the TfL fare finder (as of Jan 2023): Notice that there is a £1.8 difference for a single journey! So what's going on? To answer this question would involve looking at a fairly advanced concept that is likely to confuse the average tourist. An ELI5 (explain like I'm 5) answer would look something like this:

Wherever possible, always choose a TfL service within London. This includes the Tube, and also the Overground and Elizabeth Line, unless you plan to travel a lot that day. The more advanced explanation follows below:

When you take a journey on National Rail or TfL, you'll be classed in one of the three groups: TfL only, National Rail only, or the mixed-route option, with the average prices in increasing order.

When you take Option 2 or 3, you are taking a mixed-route journey which involves travel both on non-TfL services (here Southern/South Western Railway) and TfL services (here the London Underground). This causes your journey to be shifted to a more expensive scale which is higher than what you'd pay if you travelled only on TfL services (which would be the case with option 4, as the London Overground, while technically part of the National Rail system, is a TfL service).

Of course, if you travel enough to reach the cap for a particular day/week, then the above doesn't matter; the cap does not depend on how you travel (with the exception of the bus).

Buses
Buses within London can be a cheap way to go around London:


 * They don't have a peak or off-peak period - it's the same fare throughout the day. The single fare is generally cheaper than the cheapest Tube fare (with some exceptions if you use a Railcard and are making a non-Zone 1 journey).
 * Buses (and trams) don't have zones - it's the same fare no matter where you're going from/to.
 * Many buses operate in the night - much more than London Underground/National Rail
 * They work in conjunction with rail capping - if you've already reached a cap, you don't pay any more for buses
 * If you only use buses, there is a separate, lower cap for a day (equivalent to three single bus journeys) and week
 * Transfers between buses within 62 minutes are included in the price of a single bus fare.
 * If you have insufficient credit on an Oyster card, you can still use it for a bus (which will make the balance in the card negative). However, you will need to add credit before you use the card again - even for a transfer.

The main problem users are likely to find is speed. Buses are slow, especially in London, and some (especially within Zone 1 and in peak times) are notorious for having an average speed as little as 10 km/h. You're likely to get to your destination faster using rail services. On the other side, the slow speed makes some of these buses good for sightseeing.

Watch out - especially outside London (where some TfL buses do run), you may see buses not contracted by TfL. The above notes do not apply to these buses, as they are completely separate.

With kids

 * If they are under 5: it's free - this is true for any rail service in the UK
 * If they are between 5 and 10 (both inclusive): always free on buses, trams and when accompanied by an adult. Unaccompanied, free on London Underground and related National Rail services with a 5 - 10 Zip Oyster card (this one can be applied for by non-UK residents) - see this page.
 * If they are between 11 and 15: A 50% PAYG (pay-as-you-go, including applicable caps) discount can be set for a temporary period of time (about two weeks) for a child (up to ~16 years old) on an ordinary or visitor Oyster card, which is useful for families visiting London. This can be done by a member of staff at a London Underground station. Note that the discount is valid for both tube and bus. Alternatively the 11-15 Zip Oyster card can be applied for instead. Additionally, travel on the Heathrow Express is free for kids under 16 when either accompanied by fare-paying passengers (which is also true for first-class travel) or are travelling with proof of a same-day departure/arrival to/from Heathrow.
 * If they are 16 - 18: such users are considered as adults. Alternatively, the 16+ Zip Oyster can be used for a 50% discount on tube and bus.

It should be noted that the Zip Oyster cards need to be ordered in advance and are normally meant for UK residents - and hence if you plan to make use of them, you must apply early enough as a tourist. There is also an application fee - but the savings should quickly make up for it (unless you're travelling only for a day or two).

Using paper tickets
TfL posters discourage the use of paper tickets within London, and for a good reason. Fares are designed in such a way that it generally costs substantially more to buy a paper ticket compared with using an Oyster or contactless card (note that paper tickets are not available at all for buses and trams). This holds true even for children (see the Young Child discount above instead). Similarly, don't get a paper travelcard either. There are a couple of cases where it is a good idea to use a paper ticket however:


 * If you want to explore the London Underground system for fun, or spend time admiring the station architecture. If you enter the system using Oyster or contactless, there is a time limit by which you must complete the journey and exit the system, or you'll be penalised. While the extra charge can be refunded by calling TfL, it can be a hassle to have to do this multiple times, and hence it may be better to get a paper day travelcard (which gives you unlimited travel within the zones on the ticket for a day).
 * If all of the below are true: you have a railcard that provides off-peak discount only (such as the 16-25 railcard) and you want to travel during the evening peak period and you want to make a mixed-mode TfL + National Rail journey and you do not intend to reach the cap. The reason is that National Rail defines the peak period to be anytime before 9:30 am, and nothing more. This means that if you use Oyster or contactless during the 4–7PM period, you'll be charged with a peak fare. If you use a paper ticket however, it is defined as off-peak, and the 33% discount that a railcard provides will kick in as a result (note that there is no separate off-peak discount on a regular National Rail paper ticket unlike Oyster), bringing the cost down compared to an undiscounted peak TfL fare. In some cases it may be possible to do this with the morning peak period, depending on the railcard (as most railcards enforce a lower-bound on the fare otherwise).
 * If you want to make one, and only one, TfL journey (or only for a day), and cannot use contactless (due to the £7 charge for an Oyster card).

Now, what happens if you need to travel outside London? Things get tricky there, particularly if you use a railcard. Let's illustrate with an example - suppose you want to go from Paddington to Reading. You have a couple of choices:


 * You can use contactless. This is £26 during peak periods (as defined by TfL), and £11.6 off-peak
 * You can get an off-peak National Rail ticket for £22.6 (which is valid on the TfL evening peak, but not morning). A peak ticket costs £27.6.

On the face of it, it looks like contactless is a good choice. But what happens if you have a railcard providing a 30% discount for instance? Then the cost drops to £14.90 and £18.2 for an off-peak and peak ticket respectively - contactless is cheaper for off-peak TfL, but costlier for a peak ticket. Recall that you can't use a railcard using contactless.

What happens if you want to make a return journey?


 * If you use contactless, a return journey is simply twice a single, so £23.2 and £52 respectively
 * If you do not have a railcard and want to make a return journey on the same day, the off-peak and peak costs are £26.7 and £52.1. Notice that the return leg is effectively free if you're on an off-peak ticket, but contactless still beats a paper ticket in this case.
 * If you do not have a railcard and want to return on a different day (up to a month), the off-peak cost is £32. Again, contactless beats paper.
 * However, if you do have a railcard, the cost drops to £14.95 for a off-peak return. This beats contactless.

To add on to that, if you want to make multiple journeys in a week, contactless has capping (but not a paper ticket).

The TLDR of this is that


 * Contactless is often better, but you should compare the costs with a paper ticket before deciding to buy, particularly if you have a railcard or plan to travel on the evening peak.
 * The London fare system can be rather complex and confusing to the uninitiated, and it would not be feasible to discuss every single peculiarity as a result.

Eurorail and Britrail
This is a scheme available only to non-UK residents, where they can get train passes at a substantial discount. This section discusses how they can be used within London; a full discussion of these two schemes is out of scope for this article.

If you have a Eurorail/Britrail pass (or Rovers/Rangers) that is valid within England, you


 * cannot use it on the London Underground
 * cannot use it on London Buses or Trams
 * can use it on the London Overground
 * can use it on the Elizabeth Line
 * can use it on Heathrow and Gatwick Express (which we've noted are otherwise very costly for what they offer); the Heathrow Express cannot be used for those with a Ranger/Rover however.
 * can use it on any other National Rail service (such as Thameslink)

Note in particular the overlap between TfL and National Rail services. London Overground and Elizabeth Lines are part of TfL, but they are also part of the National Rail system. This means that schemes part of either TfL (such as capping and Oyster) and National Rail (such as Eurorail) are valid on both - which means that Eurorail/Britrail passes can be used on these two services. This can cause confusion with TfL staff unfamiliar with this scheme, so you may need to gently point out this scheme to them.

Also: some Eurorail/Britrail passes are flexible, which means that you need to activate a day's pass before using it. Using this scheme is not a good idea unless you plan to travel outside London (or cannot use it in any other way), as capping will almost always be cheaper.

If you plan to use this scheme in conjunction with Oyster or contactless, you must touch out before using the pass.

Note that reservations are not usually available (or required) for trains within London.

Using other airports



 * Gatwick: The Gatwick Express is rather expensive and unnecessary. Use regular Southern services that go to Victoria (in Central London). You can open-jaw at East Croydon (i.e, get off the train, pass through the validator and enter the system again through another train) to get a significant cost saving, though that may be difficult if you have luggage.
 * Stansted: you must buy a regular (paper) ticket; neither contactless nor Oyster would work.
 * Luton: you must either get a paper ticket or use contactless.

First class
First class on National Rail within London is useless; don't bother. You're paying for (mostly) a piece of cloth. In fact, there are a couple of ways you can use "first class" without paying extra:


 * If the train conductor announces that the train is "declassified" (usually when the train is crowded)
 * On Thameslink trains, the "first class" on the rear of the train is automatically declassified. Quoting from the website, "Where first class is available, this can be found at the very front of the train. The first class compartment at the rear of Thameslink trains is always declassified."

Note that Oyster or contactless cards provide only standard-class travel.

The "Heathrow tax"
Since September 2022, fares to Heathrow using TfL services (such as Elizabeth or the Piccadilly line) are set as peak-only, irrespective of the time of day. However,


 * this only kicks in if your journey goes through Zone 1 (see below)
 * the off-peak discount as part of railcards still work (but that would be from the peak fare)
 * Hatton Cross is not affected (if you use the Piccadilly line), and journeys between Hatton Cross and Heathrow are free.

Hence, the way to work around this would be to simply exit and re-enter at Hatton Cross.

Delays and strikes
It is unlikely for someone travelling within London to experience a delay to a level that should qualify for a (partial) refund of your ticket. Should that happen though, relevant documentation can be found at https://tfl.gov.uk/fares/refunds-and-replacements/tube-and-dlr-delays and https://www.nationalrail.co.uk/121354.aspx. The main difference is what qualifies for a refund (or delay repay) - with TfL being considerably stricter in that they do not consider things such as a one-under (person under the train) or weather - while National Rail does (everything except planned closures does).

Strikes are likely to be more common.


 * For TfL, there is basically nothing you can do, as TfL does not give any concessions based on a strike. You cannot claim a refund at all, and if you need to take alternative transport, you'll need to pay for it yourself.
 * For National Rail (except London Overground and Elizabeth Line), train operators normally would offer you a fee-free change of date or a full refund for your ticket. They can also allow you to use your ticket on TfL services (tube, bus etc) for no extra charge - but check the documentation beforehand as that is not always the case - and you must use a paper ticket. If you have a monthly or longer season ticket (or flexi), you can instead claim back the cost of a day's travel without having to travel at all. When doing so, you should normally make a refund request for the maximum possible duration (this is usually 120+ minutes).
 * The case for those with Eurail or Britrail passes seems to be rather unclear; contact Eurail in the first instance.

With a wheelchair
The key thing to note is: it's not your problem. If you cannot use a National Rail or TfL service (only about 40% of tube stations are accessible to those that require wheelchairs), simply contact a staff member - it's their job to take care of you. They can help you plan your journey using other means of transport (such as buses, which are all step-free), or provide you a taxi at their (TfL or National Rail)'s expense. You should not have to pay for a taxi (or any more than anyone else) to get to your destination. This also applies if the lift is out-of-service for any reason. Quoting from TfL's website,

If you arrive at a Tube, Elizabeth line or Overground station and the lift is unavailable, staff will help you to plan an alternative journey to your destination. If there isn't a reasonable alternative route, we'll book you a taxi (at our cost) to take you to your destination or another step-free station from where you can continue your journey.

Bypassing Zone 1
If you use the Tube or the National Rail system, there is a significantly higher cost if you go through Zone 1 in any way (this includes entering, exiting or passing through). The last of the three is not obvious and can cause some confusion.

What exactly does passing through mean? It means that your journey must not go through a Zone 1 station at all when you're making your trip. And given that there are multiple ways to go from one station to another, how do they enforce it? By the use of pink route validators (see right). In general, if there are multiple routes from your origin to your destination, TfL's system will charge the Zone 1 fare unless you touched a pink route validator along the way, confirming the exact route you took. The TfL fare finder is a good way of determining whether you need to (and where) use the pink route validator for a non-Zone 1 journey.

Are there exceptions to this rule? Rare. But there's at least one:

Another thing worth noting is to consider whether you can exclude Zone 1 from your journey by walking a bit more. Suppose you want to go to somewhere in South Kensington (which is in Zone 1 station). Instead of using that (or Gloucester Road) station, consider nearby stations that are not purely Zone 1 - in this case that would be Notting Hill Gate and Earl's Court (both of which are both in Zone 1 and 2 - which is enough since in those cases, the fare system will pick the one that's better for you). The walking distance isn't usually that much more (up to 1 - 1.5 km more than the nearest Zone 1 equivalent), and you can get a significant saving that way, particularly if you need to take that route for work (not to mention that it's good exercise). Of course, if you are in somewhere like Holborn, this would be harder to manage and wouldn't be worth it.
 * (Clapham Junction - Shepherd's Bush) to Highbury and Islington (and beyond): this works because the default route goes through Willesden Junction, but it would be illogical to force people to get off and use the validator given that one wouldn't be changing trains! The workaround would be to go all the way to West Brompton; do not touch the pink route validator there. Then take a District line train to Victoria, and then use the Victoria line to all the way to Highbury and Islington. This can result in a significant time saving, given how frequent (and quick) the Victoria line trains are, zipping through Zone 1. You cannot use Shepherd's Bush as a changeover point however, as this involves exiting the station formally (to enter the Central Line). Kensington Olympia is an acceptable alternative, through District Line trains are uncommon outside of weekends, and trains do not generally go directly to Victoria (forcing you to change at Earl's Court). If you're going beyond Highbury and Islington (on the Victoria line), you must get off and use the pink route validator on the London Overground side of the station before getting back.
 * Clapham Junction to Highbury and Islington can also be done by the anticlockwise loop (i.e, going through Surrey Quays) despite passing through a Zone 1 station; this works because the two directions cannot be distinguished by the system. This does not provide a noticeable time saying, however. This does not work for other stations along that loop.

Railcards, the 18+ Oyster or the 16+ Zip?
This is a dilemma usually faced by students studying in London. On the surface, there are two options:


 * You can get an 18+ Student Oyster card, which provides a 30% discount on weekly or longer travelcards. Importantly, there are no discounts for pay-as-you-go travel, and the automated daily/weekly capping that comes along with that doesn't get a discount either.
 * You can get a 16-25 Railcard and attach it to an ordinary Oyster card. This provides a 33% discount on pay-as-you-go off-peak travel. The automated daily/weekly capping also gets a discount for off-peak travel.

The short answer is "in most cases the latter, but it depends on your exact situation". The longer answer comes below.

As mentioned above, the student Oyster card provides a discount on travelcards. This means that you'll need to be hitting the weekly cap for the benefit to take effect. In many cases, depending on how you travel (particularly if you can travel off-peak), you won't be hitting the daily/weekly limit. As a result, the 18+ Student Oyster card is unlikely to provide value in these cases, especially if you don't commute that often. There are exceptions however:


 * The 18+ Student Oyster card provides a discount on the Bus and Tram travelcard. If you use buses regularly, it can be the case that you'll get a discount if you hit (or are close to) the bus cap limit. The Railcard does not provide discounts on buses (though they still count towards the discounted caps, depending on when you travel)
 * If you need to use National Rail, you may well be running into the National Rail premium issue (see above) and can easily hit the daily/weekly cap (especially if you need to travel peak).

It is also important to note that the two schemes are not mutually exclusive; getting a railcard in general is a good idea if you need to travel outside London (as the savings can quickly add up).

The next question that arises would be if you chose to get a Student Oyster card. You'll need to load a travelcard - do not get a yearly travelcard. The added discount (compared to buying monthly or even weekly travelcards) is small, and that would be easily offset by the fact that most would not be commuting to university during summer vacations. Cancelling a travelcard is generally punitive, as it is done by computing the expected cost of (undiscounted) tickets up to the point you cancel - irrespective of how you used the card. Remember that even weekly travelcards are eligible for the 30% discount.

Another common question arises with 18 year olds entering university - if they don't already have one, can they get a 16+ Zip Oyster card instead (which provides 50% peak and off-peak discount on tube/rail/bus, with free bus/tram for those in London)? The answer is no - while the TfL webpage does not make this clear (but does in their terms and conditions PDF for that card), 18 year olds are only eligible for the card if they are in pre-university education (formally NSQF Level 3 or below). In other words, one would be eligible if they are doing A-Levels/IB/BTEC, but not if they are in the first year of university (as that's NSQF Level 4). Those in foundation years will need to check with your university. However, if you are eligible for the 16+ Zip (for instance if you're a 17-year old entering university), the 16+ Zip beats the 16-25 railcard easily.

Boundary tickets
This is a special type of ticket that can be used if you already have a season ticket and want to go to a place that is not covered within the zones of your season ticket. There are two aspects to this:


 * If the season ticket is on an Oyster card, the process is automatic and seamless. Suppose you have a Zone 1 - 4 pass, and you make a trip from Zone 2 to Zone 6. You'll be charged only for the Zone 5 to Zone 6 portion, whether you use National Rail or a TfL service. This is useful if you have an Oyster travelcard that does not include Zone 1 and need to make occasional journeys into it. However, this does not mean that you can save money by getting a non Zone 1 pass and relying on boundary tickets if you need to make Zone 1 journeys to work - the cost of a Zone 1 - 2 journey can quickly add up. The same applies the other way.
 * If you need to use a paper ticket (either because your season ticket is not on Oyster, or because you're travelling outside London), it gets complicated. First, look up the fares via a specialist site such as https://www.brfares.com/ - boundary zone tickets should show up there. You can use railcards as appropriate. Then, you'll need to either go to a physical ticket office, or use the automated ticket machines (this depends on the operator; don't expect this to be available outside London).
 * This can also be used by Freedom Pass users (for those users, get a BZ6 - destination name ticket). Make sure that the entire journey is valid - you cannot use this to bypass the 9/9:30AM rule.

The benefit of boundary tickets is that they work like a discounted peak/off-peak ticket, providing flexibility compared to an Advance ticket. Note though that a point-to-point Advance ticket may well be cheaper than a boundary zone ticket, but you'll lose flexibility that way.

If your season ticket is on an Oyster card and you buy a paper boundary-zone ticket, you can enter the system with one mode and exit with the other (i.e, enter using Oyster and exit using the paper ticket). Remember that you do not have to touch in or out on an Oyster card that is loaded with a season ticket.

Freedom passes
This provides a way for eligible London residents to get free travel across London, with some restrictions (particularly relating to use of National Rail services)


 * The Freedom Pass provides free travel after 9AM (anytime on weekends and public holidays). All TfL services can be used without any further restriction. National Rail services within London can normally be used after 9:30AM (with some exceptions where the 9AM limit applies instead) - see https://www.londoncouncils.gov.uk/services/freedom-pass/using-pass/freedom-pass-travel-map
 * The 60+ Oyster photocard is similar to the above; however, it has a further restriction in that Elizabeth line services cannot be used west of West Drayton. See https://tfl.gov.uk/fares/free-and-discounted-travel/60-plus-oyster-photocard
 * The Disabled Persons' Freedom Pass is similar to a Freedom Pass. However, it is meant to be used by people meeting a narrow criteria (this includes hearing loss and wheelchair users). It does not have the 9AM restriction on TfL and related National Rail services, but retains the 9:30AM rule otherwise.

Now, who is eligible for a Disabled Persons' Freedom Pass? In theory, it's defined in https://www.londoncouncils.gov.uk/services/freedom-pass/disabled-persons-freedom-pass/eligibility. However, in practice, due to the wording and that given that eligibility for this scheme is decided by local boroughs, there is a degree of ambiguity and you're advised to contact your borough if you're unsure, rather than just assume that you're not eligible. A couple of examples are given below:


 * People with autism: in theory, given that autism is not technically a learning disability, such people are not eligible for the scheme. However, there is evidence that some boroughs are interpreting that section ("learning disability") differently and are treating autistic people (and even ADHD in some cases - here is an example) as eligible for the scheme. Only a few boroughs (such as Harrow) have explicitly confirmed that autistic people are not eligible; if you do not live in such a borough, ask your borough, particularly if you're eligible for schemes such as PIP (Personal Independence Payments).
 * Epilepsy: the main reason such people would be eligible for the scheme is because of rule 7 (i.e, they would not be able to get a driving licence due to seizures). However, there are some reports that suggest that one does not need to have epilepsy that serious to get the freedom pass. Also, there are other conditions that could make someone eligible for such a pass, such as bipolar disorder (example). Again, ask your borough.

What happens if you are a resident from elsewhere in England and are visiting London? If you have an ENCTS (English Concessionary Travel Scheme) card, you are entitled to free travel on London buses only after 9AM (the one for disabled persons does not have this restriction). These cards don't work on the card-readers installed in London buses, so you'll have to show your pass to the driver. The converse is also true - Freedom Pass users can access buses elsewhere in England for free. This does not apply to those with the 60+ Oyster photocard.

Gold record cards
If you have an Oyster annual travelcard (valid for any zone combination) or a National Rail annual season ticket valid within a specific region (described here), you're eligible for a Gold Record card. This provides discounts comparable to a railcard within that region, including a 33% off-peak discount using Oyster.

This provides an interesting question: what is the cheapest season ticket you can get that qualifies for a Gold record card? You can get an annual season ticket from Hatton to Lapworth for £184 (as of January 2023) - you don't need to have any connection with the area to buy a season ticket between two areas! For some, the benefits of getting the gold card are enough to buy such a season ticket, particularly when they aren't eligible for any other railcard (the Network Railcard is arguably rather unappealing, especially as it provides no Oyster discounts).

Other tips
One useful tip is that buses are always valid when using travelcards, irrespective of the zones it passes through. This can help as you can get a cheaper travelcard and use the bus for the rest of the journey, and using boundary tickets for the times you need to make journeys outside the zones. Trams are always valid as long as the travelcard includes validity for at least one of zones 3 - 6.

Going further
For those who want to read further into the ticketing system of London transport and how it can be used to optimise costs, https://oysterfares.com/ is a very good site for that.