Oyster cards for a family with teens and tweens

I can't give you specifics for your family, but we used the Oyster Cards in May around London. We put 15pd on each and were able to cash the unused portion out at the end of our trip. We purchased them the day we needed them and cashed it out on our final day. We think they are a good deal and easy to use.

I haven't traveled with kids in London, but I've been there several times and have spent more time than I want to admit, reading posts on travel forums online.

Here's my opinion for what it's worth. Don't bother buying Oyster cards ahead of time. There are TfL (Transport for London) staff at Heathrow available to answer questions. I have heard that they may not be behind a desk, but roaming in the area of the TfL ticket machines to provide help.

You can load 7-day travelcards onto Oyster cards, or in the alternative just put some amount of £££ on them. In the latter case, the system works its magic as you travel around and unless you travel outside Zones 1-2 (which is 99% of where you'll be in London), your daily fare will cap out at a certain amount. Hampton Court Palace is of course outside the central area (zones 1 - 2). I think you can use the Oysters to get there, but that will of course be an extra fare.

[Edited later to delete a sentence, because I was apparently wrong about travel to the HP studio tour.]

Honestly, I found all of this easier in practice than it is to try to describe it. I just load £££ onto an Oyster card and roam around London on Tube trains and the occasional bus, and buy the occasional train ticket for a day trip outside London. So far it hasn't bankrupted me and I've had fun.

I'm not making light of a genuine concern to have a family vacation in London and not bust the budget, however. London is expensive and you have five people to pay for.

Good luck!

I can't comment on how it works for your 10-year old, I think they need to buy a special child Oyster Card, with their photo on it (to stop an adult using it). This card automatically charges child fares.
And yes, buy the cards when you arrive, At Heathrow airport if that is where you arrive and are taking the tube in, otherwise at your first tube station. Start with £20-£30 on each card, and add more when it runs out. Every time you use he card there is a small display that shows the remaining amount.

As for your excursions, Oyster cards are valid on all transport in London, tube, bus, national rail and river boat. Both Hampton Court station, and Watford Junction (the station for the shuttle bus to the Harry Potter studio) are in the Oyster Card area.
See the all London rail map here: http://content.tfl.gov.uk/london-rail-and-tube-services-map.pdf
Hampton Court is in square A5, Watford Junction in B1, right at the top.

The special Zip Oyster cards with pictures are the absolute cheapest way for children, but the admin is convoluted for a one off visit and the issue fee won't be offset. The alternative is the Young Visitor Oyster, at half adult fare. This discount is set for a fortnight on production of passport to confirm ID.

As to how young children who travel free get through the barrier, the answer is to go together through the wide barrier or through one with an attendant.

Yes, at Heathrow there are roaming attendants at the ticket machines who will help you. There are also attendants at many other stations (can't say for sure if they all have them, at all times, but I certainly remember seeing them often).

In my case, I was in London 6 days, so I bought an Oyster with a 7 day Travelcard for zones 1-2 loaded onto it (easy to do at the machine; I used cash). I then had to figure out how to add the fare from Heathrow. I asked an attendant, and they told me it was an extra £1.50 (at midday, so off-peak fare). They helped me add it to the card (I didn't find this so easy at the machine), and I was on my way.

Something similar could work well for you. For Harry Potter and Hampton Court Palace, if you are getting a two zone Travelcard, you will similarly need to add the extra fare before travel to these places. I don't know if a Travelcard with more zones would be a better deal, since you're going several places outside zones 1 and 2 (particularly true if you're also taking the Tube back to Heathrow).

Or, you can simply use Pay As You Go (PAYG) with "daily capping." This means you start by buying an Oyster (£5) and putting money on it (say, £30). Each time you travel, the fare is deducted, but once you reach the daily limit, no more fares are deducted that day. If you stay in zones 1 and 2, the daily cap is £6.60. On the days you go outside zone 2, the cap will be higher. The advantage of this method is you don't have to think - just tap in and tap out, and the Oyster system keeps track. When your balance gets low, just add money to the Oyster card. The disadvantage is that it may be more expensive than a 7 day Travelcard.

Remember each person needs their own Oyster, whether you are getting a 7 day Travelcard or using PAYG. At the end of your trip, you can get a refund on both the amount left on the Oyster as well as the £5 fee for the card itself - IF you have made sure to use the same payment method every time (either cash, or the same credit card). Or, you can retain it for future trips; apparently the value on it doesn't expire, but if it's been a long time since the last use, it may have to be reactivated by station personnel.

In London with my husband and 4 children (11, 17, 19, and 21) this past week for 3 days. Took Eurostar from Paris to London. Purchased 6 regular price Oyster cards from the machine in King’s Cross Station. Also stayed in Pimlico. Used 16 pounds for each person on the tube/bus over the course of 3 days. “Cashed out” Oyster Cards at Kings Cross on our way out of London and retrieved the 5 pound deposit plus any residual balance. We cashed out at a machine and received the balance in coins. Note that each Otster card must be cashed out individually.

In London with my husband and 4 children (11, 17, 19, and 21) this past week for 3 days. Took Eurostar from Paris to London. Purchased 6 regular price Oyster cards from the machine in King’s Cross Station. Also stayed in Pimlico. Used 16 pounds for each person on the tube/bus over the course of 3 days. “Cashed out” Oyster Cards at Kings Cross on our way out of London and retrieved the 5 pound deposit plus any residual balance. We cashed out at a machine and received the balance in coins. Note that each Otster card must be cashed out individually.

We were just in the UK for two weeks. My 13 year old had her own Oyster card. It didn't charge as much for her because she is a kid. My nine year old did not need one. Children that young are free and don't need an Oyster card as long as they are with a paying adult. We would usually use the wide stiles that are for handicapped or strollers. They seem to stay open a little longer, and there is often a worker right there. Otherwise, she would just follow really closely as we hurried through the stile.

I should add that we got our Oyster cards at Heathrow when we arrived, and the lady at the desk did whatever was necessary to my older daughter's card to make it charge her less. They were very helpful.

Your 10 year old does not need a card. He can simply go through the stiles at the same time as an adult. This worked perfectly well with my 9 year old last summer. Your 14 yer old will get his own card but they will code it as a youth card so that it debits the lower fee when he goes trough. The attendant put a star on my daughter's so we knew which one was hers. My husband and I each got a regular card. Do not pre-purchase. Simply find the kiosk at Heathrow and the attendant can help you get all the right cards. We started off with 20 pounds on each of the adult cards and 10 on the youth card and then added as needed. It is easy to add at the machines in the stations. As someone else here said, cash out before leaving the airport and you will get all your money back.

Finally, I feel like this is the simple matter I suspected it must be. Thanks to all for taking the time to respond!