Islands are beloved Thai destinations, and thankfully, there are still some islands where you won't have to fight the crowds. Enter:
Koh Kood. Next to the more popular Koh Chang, Koh Kood has lovely beaches, clear waters, and great snorkeling and dive sites. The island is mostly covered in forest with limited infrastructure (so no banks or ATMs), but a growing number of resorts offer relaxing vacations. If you have time, check out Ao Salat, a traditional fishing village, to see the island's true local culture.