Shark Bay Dive Site: Koh Tao's Best Bay for Turtles and Reef Sharks

Shark Bay (Ao Thian Ok, also written Thian Og) is the best-known place on Koh Tao to snorkel with wildlife. Green sea turtles can almost certainly be seen every day, and blacktip reef sharks, eagle rays and reef fish are around all year. From March to May, baby blacktips gather in the shallows near the seagrass.

It is mainly a snorkelling and freediving spot, with only occasional scuba. The coral starts a few kicks from the shore, and depth builds to roughly 8 to 15 m further out.

Shark Bay dive site map

1. 1Sandy beach
2. 2Seagrass beds, 0-3 m
3. 3Damaged central reef, 2-10 m
4. 4Eastern reef, 2-12 m
5. 5Western headland reef, 2-12 m

Getting to Shark Bay, Koh Tao

The bay sits at the southern end of the east coast, next to Sai Daeng and a headland to the west. You can reach it from Chalok, Mae Haad or Sairee by taxi, longtail or scooter, and it is a 10 to 15 minute walk from New Heaven Dive School. Resorts on the west coast have no direct access.

Entry from the small sandy beach, which has a bar, is free. You can also enter across the rocks via Ok2 or Mama Jim bungalows for a small fee.

Snorkelling with turtles and sharks

Most visitors come for two animals. Green sea turtles can almost certainly be seen every day, and a slow, quiet approach gives the best views. Blacktip reef sharks cruise the sandy edges and reef margins, and they are easiest to spot in the morning.

From March to May the seagrass in the shallows becomes a nursery for baby blacktips. They are small, nervous and very easy to scare, which is why the rule of never chasing or touching anything matters most here. Float, watch and let them come to you.

What the bay looks like underwater

A sandy beach and seagrass beds grade into patchy coral reef. The seagrass is where the baby sharks like to gather in season.

The centre of the bay was hit by mass coral bleaching and has been slow to recover, so the degraded coral there is not the main attraction. The most life is on the eastern side towards Sai Daeng and along the western headland. The map is schematic, not surveyed.

Marine life at Shark Bay

• Green sea turtles: almost certain on any day, best in early morning and late afternoon.
• Blacktip reef sharks: best seen in the morning, shy, and not a danger if left alone.
• Baby blacktips: March to May, in the shallows by the seagrass.
• Eagle rays and reef fish: groupers, parrotfish, butterflyfish and angelfish.
• Small stuff: pink skunk clownfish and cleaner wrasse.

The healthiest coral is on the east side near Sai Daeng and around the western headland, so if the central reef looks worn, keep swimming rather than turning back.

Best time to visit

Go in the morning for the sharks, and early morning or late afternoon for the turtles. March to May is the time for baby sharks. Rainy or windy weeks make the bay less pleasant, and conditions can change in bad weather.

Water clarity is good in the right season, though it is not something we can put a number on.

Shark surveys and conservation

New Heaven's reef team runs regular shark surveys in the bay. The animals here are wild and the numbers are monitored, so how you behave in the water matters.

Because this is a free, shore-access bay with no guide required, it is worth being a good example for the next group. Take your rubbish with you, avoid standing on coral, and keep your fins away from the seagrass.

Tips for snorkellers

• Bring your own mask and snorkel, and an underwater camera if you have one.
• Never touch or chase the animals, and keep a respectful distance from sharks and turtles.
• Go with a group or at least a buddy.
• Wear a rash vest or reef-safe sun protection. There is little shade.
• Watch your footing on the rocks at the entry.

Safety notes

Boat traffic passes through the bay, so stay visible. Sun exposure is the main everyday risk, and the rocks at the entry can be slippery.

Check the weather before you go. Conditions can change in bad weather, and a windy or rainy day is better spent somewhere else on the island.

Finally, remember the practical side of a shore snorkel: carry water, wear sun protection and tell someone where you are going, especially if you are heading out along the edge of the bay.

Why dive Shark Bay

• Green turtles almost daily
• Blacktip reef sharks
• Baby sharks March to May
• Free beach entry
• Regular shark surveys by New Heaven

Shark Bay: frequently asked questions

Nearby dive sites

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