Yes - bring some Thai Baht for taxis, markets, massages, and small shops. Most hotels and restaurants also take cards.
Stick to bottled water. Hotels usually provide it daily in your room.
There isn’t Uber on Koh Samui, but there are plenty of local taxis, and most resorts can call a taxi for you. Make sure to have Thai baht on hand to pay.
U.S. passport holders do not need a visa for short tourist visits. Please make sure your passport is valid for at least six months beyond travel dates.
Warm and tropical. Typically 80s°F during the day. Lightweight clothing is best.
Because Thailand is a long trip, we recommend arriving a couple days early to adjust -many guests stop in Bangkok first.