It does and it doesn’t!
Yes it generally does work it most stores that accept contactless payments.
The one thing I can never ever get ApplePay to work on is when using the Uber app when in the US. It will always decline the transaction for some reason. I have to pay using PayPal.
I did have an issue with an ApplePay transaction last year in Fort Lauderdale. Paid for a meal in a restaurant using ApplePay. The transaction went though OK, however, when the restaurant adjusted the bill total to include the tip I left, ApplePay decided to decline which caused the whole charge to get declined as well. I got a very apologetic but pleading email sent to me asking if I would mind returning to the restaurant and using a physical card. I’d made the reservation via OpenTable so they had my contact details. As it’s a restaurant I use regularly and as my hotel was just around the corner, I was happy to go back and settle up!
I’ve also have a few large transactions blocked when paying for hotel stays generally down to the card fraud system kicking in automatically and blocking the card. Once you reply to the automated SMS message from the card issuer; the card is unblocked and good to go within a few minutes.
On the whole though, UK ApplePay does work anywhere globally. Just remember though that any foreign transaction fees will still be added for some card providers….one of the reasons why I never use my VS MasterCard or AmEx card in the US as foreign exchange fees can soon add up
I have a Barclaycard Rewards card for all my foreign travel transactions as that has zero foreign transaction fees + cashback.