Mango Bay Dive Site, Koh Tao: Depth, Map & Snorkelling

Mango Bay, also called Ao Muang or Aow Muang, is a wide, curved bay on the north coast of Koh Tao, ringed by jungle with a small sandy beach at the back. It is the dive site the island uses to start people off: shallow, sheltered and almost free of current. Boats run from Sairee in about 15 minutes, and a jungle road from Sairee now reaches the bay too, so you can also arrive overland.

It would be easy to write Mango Bay off as a training patch, but that undersells it. A big sandy bowl fills the middle, coral reef climbs the sides, and boulders spill down from the shoreline. That mix gives you giant clams, barrel sponges, rays and barracuda, plus plenty to find on the sand if you slow down.

Mango Bay dive site map

1Beach, south shore
2Sand bowl, 4 to 14 m
3East coral garden, 2 to 10 m
4West boulders and drop-off
5Boulder swim-through
6Boat drop, about 16 m
7Artificial structures, north edge

Usual route: Boat divers drop in the outer bay at about 16 m, cross the sand toward one side and work up the reef toward the beach; experienced groups may follow the west drop-off in. Drawing based on local dive briefings: approximate, not to scale and not for navigation. Your guide's briefing on the day always comes first.

Diving Mango Bay: the route

Boat divers usually drop in the outer bay at around 16 m, cross the sand toward one side, and work up the reef toward the beach. Experienced groups are sometimes dropped on the west side to follow the drop-off along the coastline into the bay.

Most of the dive is spent at 6 to 12 m, which means long bottom times and plenty of air left for looking around. Mango Bay is often paired with Japanese Gardens on a two-dive trip.

For new divers, this is the place where the first breaths underwater happen. The sandy floor is perfect for skills and buoyancy practice, and the reef at the edges is close enough that you never feel like you are doing a drill. Open Water course dives, Discover Scuba Diving, refreshers, Underwater Naturalist and photography courses all use the bay.

Underwater layout

The bay opens to the north, with the beach at the southern end. A flat sand floor fills the centre and slopes gently from the shore to around 12 to 14 m, deepening to the mid-teens offshore. Reef runs along both sides of that sand bowl.

Guides describe the sides a little differently, so treat the arrangement as approximate. In general you will find a coral garden of staghorn, mushroom and table coral with barrel sponges on one side, and bigger boulders on the other, with a drop-off following the west coastline. A swim-through is reported among the boulders. Listen to your briefing, because your guide will tell you exactly where things are that day.

Some guides mention artificial structures along the northern edge of the bay, though we have not been able to confirm them.

The sand patches between the coral heads are worth a slow look, because that is where the small critters sit. The shoreline end of the bay is the shallowest part, and the whole bowl is simple to navigate.

Marine life at Mango Bay

The reef side gives you the easy wins. Giant clams and big barrel sponges sit among the rocks, and yellowtail barracuda, Jenkins whiprays and blue-spotted stingrays are regular sights. Fusiliers, snapper, parrotfish, red-breasted wrasse, longfin bannerfish and titan triggerfish move through the coral.

Occasional: eagle rays, green and hawksbill turtles, seahorses and juvenile harlequin sweetlips.
On the sand: crocodile snake eels, peacock sole, gobies, sea moths and white-eyed morays.
Rarer treats: Spanish dancer and Persian carpet flatworms.

Snorkelling at Mango Bay

This is one of the better snorkel spots on the island. The water is calm, a roped-off swim area sits on the east side, and the boulders along the shore are easy to follow without any navigation worries. Mind the boat traffic near the rope line and stay inside the marked area.

Conditions and best time to dive

Current inside the bay is little to none. The drop-off along the west coastline can feel a touch more active, but nothing a normal diver will struggle with. Visibility is commonly 8 to 20 m and moves with the plankton through the year, so some days are clearer than others.

The bay is calm for most of the year and makes a good fallback when other coasts are rough. March to September is generally the best stretch.

Depth figures vary by operator, anywhere from 1 to 20 m depending on where they measure, but the typical profile is 6 to 12 m and the boat drop on the second dive is around 16 m. Plankton levels are the main thing that affects clarity, and there is no strong seasonal closure.