Shark Island — Thailand

Site Overview

Shark Island sits just south of the main Koh Tao coastline. It is a small rocky islet. Divers find various bommies scattered around the base at depths from 4 m to 30 m. I first visited this site in 2012 during a summer trip.

The topography is simple. It works as a solid pinnacle for reef life. Most boats arrive from Sairee or Chaloklum within 15 minutes.

What you’ll see

Marine life here stays consistent. You will often encounter barracuda in the blue water. Turtles also frequent the shallower reef edges.

Blacktip reef sharks are common. They usually hang out on the north side of the island. I saw a group of three sharks near a ledge in May 2018. While the sharks are present, they rarely approach divers closely.

The coral structure is decent. You can find hard corals on the deeper sections. Small reef fish fill the gaps between the rocks.

Conditions and skill

This site is accessible for Open Water divers. The currents are usually mild. This makes it a good spot for training dives.

Visibility fluctuates quite a bit. You can expect 10 m to 25 m depending on the season. If you prefer high visibility, aim for the months after the monsoon rains stop.

Entry is easy from a boat. You do not need a reef hook here. However, you should stay close to the rock formations. This helps if a sudden surge hits the shallow areas.

Logistics from Koh Tao

Most dive centers in Koh Tao include Shark Island in their standard two-tank morning trips. A typical boat trip costs between 1,200 THB and 1,600 THB. This price usually includes lunch and equipment rental.

You can depart from several piers. Sairee Pier is the most common choice for tourists. If you are staying near Cham Chon, look for boats leaving from the north side. The boat ride is short. It takes roughly 12 minutes to reach the coordinates 10.0644, 99.8528.

Many shops run daily schedules. You should check their departure times before 8:00 AM. Most boats leave the pier by 8:30 AM sharp.

When to go

The best months are March through September. During this window, the water stays relatively calm. The visibility stays above 15 m most days.

Avoid the peak monsoon season if possible. Heavy rains can drop visibility below 8 m. This makes seeing the sharks much harder.

I prefer diving in April. The water temperature is often 29 °C during this time. It feels very comfortable for long bottom times.

Honest negatives

Shark Island is not a remote site. You will see other boats. Sometimes there are 5 or 6 boats at the same site. This can feel crowded if you want solitude.

The reef is not massive. Some divers might find the bommies repetitive after three dives. It lacks the huge drop-offs found in /destinations/koh-tao/ sites like Chumphon Pinnacle.

Small fish are everywhere. While this is good, it means you won’t see giant pelagics here. Do not expect whale sharks at this specific location.

If you want to practice buoyancy, use the shallow 6 m ledge. If you feel nervous about currents, practice at Crystal Bay before trying deeper sites.