Koh Tao aka Turtle Island is a small island in Southern Thailand. It's widely known as the best diving and snorkelling spot in Thailand. It definitely has more of a laid back backpacker vibe to it.
We ended up staying by Sairee beach, since it was more affordable than the rest of the island.
Things to do
Dive
If you want to dive in Thailand, Koh Tao is a great start. There's tons of dive shops here. I mean, there's TONS. You'd probably have a hard time choosing one if you didn't already have a recommendation. If you want to get certified, you'll need to choose if you want to get PADI or SSI certified. That should narrow your search.
We didn't end up diving because we were feeling pretty run-down. Plus, it takes 3-4 days to get fully certified. Although, we were planning to go with Roctopus since they train you in groups of four.
Lastly, Koh Tao used to be a great dive spot, but it's overrun with tourists now. If you have the opportunity to dive in a different country, I'd choose that.
Snorkelling
Since we didn't dive, we opted for snorkelling instead. It's more affordable, can be done without training and gives you a taste of what it's like underwater. There are tours advertised throughout the island at tourist agencies as well as hostels. They're all more or less the same. It costs 750 baht for a full-day trip. It includes your transit, snorkelling equipment, lunch, water and fresh fruit (watermelon and pineapple).
Sairee Beach
What we noticed was that Sairee Beach isn't really a great place to hangout. The sand is coarse and taxi boats are parked by the shoreline. This makes lounging and swimming a bit more difficult. However, if you want to walk by the beach and enjoy the view, it's good. A lot of restaurants, hotels/guesthouses and diving shops line this beach, so it makes a nice nightly stroll. If you wanted a good place to swim, I'd recommend Koh Chang.
Massage
There's tons of massage parlours throughout the area. There was even one beside our guesthouse. The prices will range depending on the parlour, so keep in mind that you get what you pay for. Since we don't need a luxury experience, we went for a cheaper place. To give an idea, we paid 350 baht/hour for an oil massage.
Nightlife
The nightlife here is pretty good. They'll have fire shows on the beach and the bars will be crowded.
Where to Eat
Rose Garden
Since this was beside our guesthouse, we came here almost every morning for breakfast. It's alright, with decent pricing. Nothing really stood out to us. We went out of convenience in the hot weather.
Cafe de Lotus
This is a good lunch or dinner spot. It's by the beach, so you'll have a nice ocean view. They have lunch deals with includes a meal with a drink. Our favourite dish here was the massaman curry!
Food stands
Along the smaller streets by Sairee Beach, there are a few food stands have offer cheaper meals. We usually stopped by the stands selling banana and chocolate rotees for dessert! Yum!
Where to Stay
Pranee Guesthouse
We stayed here for a four nights and switched rooms quite often. A fan room costs 700 baht and an AC room costs 1300 baht. If you can afford it, an AC room is ideal in the sweltering heat. We stayed in a fan room for three nights, and then got an AC room for the last night.
There rooms here are pretty roomy and the washrooms in the fan room are pretty nice. I like that the shower has a small wall separating it. Since the fan is small, it doesn't move the air too well, so the room is really hot. I recommend opening all your windows, but either way, it's going to be uncomfortable unless you're use to the heat.