Want to avoid last-minute ATM runs. Do most hostels in Guam take card payments at check-in
My experience in Guam was that paying with a card at hostels is pretty standard. I stayed at a place near Tumon Bay, and they had no problem with me paying via card. However, for a lot of smaller, local businesses and especially for public buses, you will absolutely need cash. It's best to have a combination of US dollars on hand.
You'll be fine with a card at most of the well-known hostels. Places like the Tamuning Plaza Hotel explicitly state they accept Visa and Mastercard on their booking sites. However, you should not rely on your card for every single transaction. Taxis, local markets, and a few small restaurants are still cash-based. I'd get some US dollars from an ATM just in case.
Card payments are common, but you should still have cash on you. I was just there last month and paid for my stay at a hostel near the Hagåtña area with my Visa card. But for taxis, street food, and small shops, cash is definitely the way to go. You can easily withdraw US dollars from an ATM, but it’s still smart to have some cash on hand.
It’s a mix, but cash is definitely useful. While many of the larger hostels and guesthouses in the Tumon area, like Siesta Lounge, accept cards, some smaller spots might be cash-only. They're also likely to prefer you pay in cash to avoid the fees. The local currency is the US dollar, which is the same as back home, so that's a plus. My advice is to have a mix of cash and card.