Given the could-be-anywhere development of the big beaches on Samui, like Chaweng, it's surprising that you can find places almost untouced just a short boat ride away. Just off the southern tip of Samui is the tiny island of Koh Taen. The island can be reached via local boats from the fishing village of Thong Krut, not far from the Laem Sor Pagoda. The trip there takes just 15 to 20 minutes.
There is just a small village on Koh Taen, with very limited tourist facilities, like one restaurant and a few humble bungalows. Generally, there's no electricity until night-fall. This all means you might well have the entire long beach on the eastern side of the island to yourself.
But, there's a lot more to the island than a nice white sandy beach. At the southern end of the beach is a reef that makes a great snorkeling spot, with lots of coral heads full of fish just below the surface. You will need a boat to reach the best spots. If that's not enough, the island of Koh Mak Sum, which faces Koh Taen, has its own powdery white beach, reef good for snorkeling, and is generally unoccupied.
But wait, there's more - as they say. On the west side of Koh Taen in a mangrove forest, with a well-built boardwalk runnng through it so you can ge close to nature. You'll be amazed at how quiet it is on this island. There are no cars or motorbikes, and with no electricity, there aren't even any boom boxes blaring. It can be all thmazing given that you can be back in your hotel room in a half an hour or so after leaving the island.
Very few local tour operators offer trips to Koh Taen. If you want to try it on your own, you will need to make your way to the fishing docks at Thong Krut, then negotiate with one of the boats to take you there. See the Thailand for Visitors Samui map for a general idea of where you're going.