Southwest Pinnacle — Thailand

The Profile

Southwest Pinnacle sits 20 km from the Koh Tao coastline. It is a massive underwater structure. The depth ranges from 6 m at the top to 30 m on the slopes. This site offers much more open water than the local Chumphon Pinnacle. I first visited this spot in 2016 during a heavy monsoon season. The visibility was only 12 m that day. However, typical visibility usually stays between 15 m and 30 m.

It is a remote location. You will feel the ocean’s scale here.

What you’ll see

This site attracts larger pelagics. You can expect to find schools of barracuda circling the edges. They often hang in the blue near the 25 m mark. Whale shark sightings are frequent here. I saw one in April 2022 during a morning dive. These sightings are most consistent between March and September.

Small reef fish live on the pinnacle itself. The structure provides a hard surface for corals. You might see some soft coral growth on the edges. It is not a colorful reef site. The focus is on the big animals.

Conditions and skill

This is an advanced site. You need at least 30 logged dives to feel comfortable. The currents are moderate. They can change quickly because of the deep ocean swells. You must carry a large SMB. A reef hook is also useful for staying stationary.

Buoyancy control is vital here. If you struggle with trim, stay at closer sites like /dive-sites/crystal-bay/. The surge can be strong near the top. Always check your air consumption early. Deep dives require strict nitrogen management.

Logistics from koh-tao

Most boats leave Koh Tao early in the morning. You will spend about 45 to 60 minutes on the boat. This is a long transit. Most dive centers charge around 1,500 THB for a two-dive trip including lunch.

Check your boat’s fuel levels. Long trips require reliable engines. I once saw a boat struggle near the 15 km mark. Always pack extra water. The sun is intense on the open sea. Most divers meet at Sairee Pier around 8:00 AM.

When to go

The best months are March through September. This window offers the most stable weather. You will see better visibility during these months. I prefer diving in May. The water temperature stays around 29 °C.

Avoid the late monsoon season. Wind can make the boat ride very rough. High waves increase the risk of seasickness. If you visit in October, expect lower visibility. The plankton levels rise then. This attracts more fish but clouds the water. Plan your trip for the dry season to maximize sightings.

Honest negatives

The distance is a drawback. You spend a lot of time traveling. It is not a relaxing boat ride for everyone. The site can also be very crowded. Several boats often arrive at the same time. This makes it hard to find a quiet spot.

Visibility is not guaranteed. Sometimes the water stays murky for days. You might swim for an hour without seeing big fish. It is a gamble every time. Do not expect a guarantee of a whale shark. Nature does not follow a schedule. Some days you only see small reef fish.

Planning your trip

Read about local weather patterns first. Check the /destinations/koh-tao/ guide for seasonal shifts. If you are new to currents, do not start here. Practice in shallower areas first. If you want big animals, this is the place.

Check your gear before leaving the pier. Ensure your computer is fully charged. If you have never used a reef hook, practice in a pool or calm bay first.