Originally Posted by
tmiw
I don't think it hurts to try tapping the physical AmEx card the first time. The best case is that it works and OP doesn't have to spend a few minutes trying to deal with a ticket machine while jetlagged. Worst case, OP pays the £5 deposit for Oyster anyway.
Anyway, in my experience NFC with my phone worked the first time close to 100% of the time. The one or two failures that I ran into resolved themselves on a second tap. This was not using AmEx of course.
Definitely no harm trying with the physical AmEx, but for some reason I understood that OP was going to have more than one passenger in the party, so additional passenger(s) would need to buy an Oyster or mess with smartphone apps.
I've never had an issue with Google Pay at Tube faregates, but I've had enough card readers on buses refuse to play nice that I don't use it. That may be particular to my phone, but it works 100% of the time elsewhere so I'm not sure.