Is American Express (Amex) accepted in Montserrat?

It’s a bad idea to rely on your Amex here. I was there with my Amex and it was a real struggle. Outside of the big tourist spots and perhaps a couple of larger restaurants, it was useless. You'll find that most places on the island prefer cash, or at the very least, a Visa or Mastercard. So, for a smooth trip, get a Visa or Mastercard from a bank with no foreign transaction fees and use that for any payments you can, and always have cash for the rest.

No, you won't be able to use Amex widely. Your best bet is to get cash from an ATM with a Visa or Mastercard. While a few places might take credit cards, they are not common, and even the ones that do might charge you an extra 5% fee, which is a total rip-off. It's much simpler to just get cash and have a backup Visa or Mastercard for the rare occasion a place takes it.

You should absolutely carry a backup. I tried using my Amex at a few places, and the vast majority of local businesses and guesthouses did not accept it. The card readers are often a bit old and just won't process it. The best strategy is to have a Visa or Mastercard as your main card and plan to use cash for almost everything. US dollars are widely accepted too, so bring some of those.

You're definitely going to want a backup card. Montserrat is a place where cash is still king. I was there last year and even in the capital, Little Bay, many of the smaller shops and restaurants only took cash or occasionally a Visa or Mastercard. While some larger hotels and supermarkets might accept Amex, it’s not widespread. The Bank of Montserrat is the only local bank, and even their ATMs are often only for their own customers, so you'll need a Visa or Mastercard to get cash out.