London Transport

just using my mobile contactless card.

This one.

TfL.gov.uk

But you will need a train ticket to go to Oxford

nationalrail.co.uk

Each person will need their own contactless card or device

I used my Apple Watch for contactless payment the last few trips in London. Saves having to fumble for a card to swipe. Remember to swipe in and out as to not be charged the max fare rate.

I just wanted to mention that the City Mapper App is my absolute favorite for navigating public transport in London.

Thanks all. So I gather there’s no real cost disadvantage to pay as you go vs buying one of those travel cards?

OP: no, no cost disadvantage. And no seven quid (non-refundable) deposit for an Oyster card.

Citymapper is excellent. I also use the TFL app a lot, because it gives live bus arrival times, and I am Queen of the Buses. :-)

So I gather there’s no real cost disadvantage to pay as you go

It’s the cheapest option.

Tap in and tap out in the tube, tap in only on the bus.

For a day trip to Oxford, you can buy an Off-Peak Day Return ticket the day of travel. It will cost around £36. The only stipulation is you have to travel during off peak times, which means leaving London after 9am.

Thank you!!

So, to clarify, I could just use my credit card (contactless option) to pay my tube fare---no Oyster card needed, correct? Thanks!

I also used my Apple Watch, not only for the Tube, but practically everything else in the UK (and a subsequent trip to Italy).
Karen: yes, just use your contactless CC.