Lighthouse Bay Dive Site, Koh Tao & Lighthouse Pinnacle

Lighthouse Bay sits at the north-eastern tip of Koh Tao, named for the tiny lighthouse on the cliffs above it. It is a small, sheltered bay with a sandy beach, a granite shoreline and steep jungle on three sides. Dive boats take 15 to 25 minutes to reach it, and some trips go by taxi to the east side and a shuttle boat instead.

The bay is shallow and calm enough for snorkellers, first-time divers and photographers, with dense coral and plenty of small life. Just offshore, about a five-minute swim north, Lighthouse Pinnacle gives more experienced divers a taller, deeper dive in the same spot.

Lighthouse Bay dive site map

1Small beach and granite shoreline
2Shallow coral field, 3 to 6 m
3Rock wall and coral, 5 to 14 m
4Sand slope to 14 m
5Northern boulders, 6 to 14 m
6Lighthouse Pinnacle, top 5 to 8 m
7Roped snorkel zone

Usual route: A boat drop on the edge of the bay, then a slow drift along the rock wall and coral field into the shallows, with the option to swim north to the boulders and Lighthouse Pinnacle first. 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 Lighthouse Bay: the route

The usual plan is a boat drop on the edge of the bay, then a slow drift along the rock wall and coral field into the shallows. It is a relaxed dive that keeps you in the 3 to 14 m range, with plenty of time to look closely at the coral.

Divers who want more can swim north first to the large boulder formations on the northern side, and on to Lighthouse Pinnacle.

Lighthouse Bay is used for Discover Scuba Diving, Open Water course dives, refreshers, Underwater Naturalist and photography courses, thanks to the shelter and shallow depth. Photographers like the coral field, where the subjects are shallow and close.

Underwater layout

The bay is a shallow bowl opening to the north-east. Close to the beach, a coral field sits at 3 to 6 m. It gives way to sand and a rock wall with coral displays between roughly 5 and 14 m. Granite boulders and coral bommies are scattered across the slope.

Toward the outer reef edge the bottom may continue to around 18 to 22 m, depending on where you measure. The northern rocks hold the biggest boulders and are where experienced divers like to spend their time. Roped snorkel areas sit near the shore.

The depth figures differ a little between dive centres. Most put the coral field at 3 to 6 m and the maximum at 12 to 14 m, while one describes the range as 5 to 18 m. Either way, the heart of the dive is the shallow, colourful part, and you will not need to go deep to enjoy it.

Marine life at Lighthouse Bay

Turtles are often seen grazing in the shallow coral field, which is one of the best reasons to come. Table coral, staghorn and mottled coral are dense here, and barrel sponges and table corals act as apartment blocks for small fish. Anemones on the boulders shelter pink anemonefish.

Common: yellowtail barracuda, Weibel's and lined butterflyfish, longfin bannerfish, red-breasted wrasse, parrotfish, sergeant majors, blue-spotted stingrays and titan triggerfish.
Now and then: a blacktip reef shark, green turtles, king mackerel, and ornate ghost pipefish in the calmer months.
Macro: Christmas tree worms, nudibranchs, wart slugs, ghost shrimp, Durban dancing shrimp, and crabs and morays in crevices.

Lighthouse Pinnacle

Lighthouse Pinnacle is a separate granite tower just offshore, about a five-minute swim north of the bay. It rises from around 25 to 30 m up to within roughly 5 to 8 m of the surface, with swim-throughs and ledges to explore on the way.

Current here is mild to moderate and lighter than at some east-coast sites, though stronger water can show up past the headland. That makes it Advanced-friendly: a good second dive if you have the depth certification and want something more dramatic than the bay.

Depth: roughly 5 to 8 m at the top, 25 to 30 m at the base.
Highlights: swim-throughs, ledges and a vertical granite structure.
Tip: keep an eye on your depth and no-stop time, because the rock invites you down.

Note that depths at the pinnacle vary with where you measure, and the top can sit anywhere in the 5 to 8 m range. The rock is also a short swim from the bay, so some groups combine the two on a single dive, while others return for it as a second dive.

Conditions and best time to dive

Inside the bay there is little to no current. Visibility is usually 5 to 10 m, and up to 25 m or more on a good day, and it is better in the calm months. March to October is the best stretch, and the bay is also dived during the June to September south-west monsoon.

From late October into the north-east monsoon, the water gets rough and murky. The eastern side is generally avoided and boats use the western side instead.