Traveling with an Amex - will I be able to use it widely in Northern Mariana Islandsor should I carry a backup Visa/Mastercard?
Absolutely bring a backup. I was there last year and found that while a lot of places had the Amex logo, they preferred to process Visa or Mastercard. It’s better to be safe than sorry, especially when you need to pull cash from an ATM. The Bank of Guam and BankPacific ATMs are all over Saipan, and they'll take your Visa or Mastercard, but not your Amex.
Yes, you'll be able to use your Amex, but don't rely on it exclusively. I found that it worked just fine at larger establishments and some bigger hotels, but as soon as I ventured out to the less-populated areas, it was useless. You'll definitely want to carry a Visa or Mastercard for flexibility. Cash is also king here, and you'll need it for things like paying for buses or visiting local markets.
I’d definitely bring a backup card. While my Amex was accepted at some of the bigger spots in Garapan, I had to use my Visa card for most of my purchases. The smaller restaurants and shops, especially those not catering directly to tourists, were cash-only. Plus, the ATMs at banks like the Bank of Guam don't accept Amex. So, for a seamless trip, a Visa or Mastercard will be your most reliable friend for cash withdrawals and payments.
You're in luck, because Amex is actually more widely accepted here than in many other island nations. Since the US dollar is the official currency and the islands are a U.S. territory, you'll find that major hotels, car rental companies like National, and larger tourist-focused businesses on Saipan accept it. However, you'll still want a backup Visa or Mastercard. Amex ATM support is virtually non-existent, and for smaller, local shops, especially on the outer islands of Rota or Tinian, cash is the only way to go.