Richelieu Rock (Similan) — Thailand

The Pinnacle Structure

Richelieu Rock is a steep pinnacle. It rises from 32 m up to 8 m depth. I first dived here in 2014. The coral growth is dense. You will see soft corals covering the rock surface. It sits at 9.3667, 98.0167 in the Andaman Sea.

This site is not a flat reef. It is a vertical wall. Most divers stay on the upper slopes. The structure attracts massive amounts of life. This happens because the rock creates a natural upwelling.

What you’ll see

Expect large schools of fish. Barracuda often hover in the blue. I saw a school of 50+ barracuda in 2018. Trevally also patrol the edges of the rock. You might see manta ray passing through the site. They prefer the cleaner water away from the rock.

Whale shark sightings are common here. They appear most often between February and April. This is the peak season for big pelagics. You should keep your eyes on the blue water. Do not miss the smaller details too.

Sometimes the visibility changes fast. It usually stays between 20 m and 40 m. You will see many reef sharks near the bottom. The biodiversity is very high here. Many divers call this the best site in Thailand.

Conditions and skill

This is an advanced site. Currents can be moderate to strong. You must have good buoyancy control. I recommend carrying a reef hook. This helps you stay still without touching coral. You also need a large SMB for safety.

Do not dive here if you are a beginner. The surge can push you into the rock. You need at least 30 logged dives. Some operators require an Advanced Open Water certification. This ensures you can manage depth and current.

Watch your air consumption carefully. The current makes swimming harder. You might use 20% more air than usual. Stay close to your buddy at all times. Safety is the priority here.

Logistics from Phuket

You cannot reach this via day boat. It is too far from the coast. Most divers take a liveaboard from /destinations/phuket/. These trips usually last 4 or 5 days. You will leave from either Phuket or Khao Lak.

A typical 4-day trip costs roughly 1,200 USD. This price includes most meals and dives. Check if the boat includes gear rental. Some agencies charge extra for tanks or computers. Always ask about the fuel surcharge before paying.

Most boats depart in the morning. You will spend several hours traveling to the Similans. The distance is significant. It is worth the travel time for the diving quality.

When to go

The best months are February, March, and April. The water is warmest then. Visibility is also at its highest levels. This coincides with the whale shark season. Many divers plan trips specifically for these three months.

Avoid the monsoon season from May to October. The seas become too rough. Most dive operators close the Similan parks then. You will face heavy rain and low visibility. It is not a good time for this region.

Plan your trip early. The best liveaboards book up months in advance. If you want February, book by November. This ensures you get a boat with good reviews.

Honest negatives

The crowds can be intense. Many boats visit the same site. You might share a dive with 40 people. This makes it hard to see large animals. It also puts pressure on the reef.

Liveaboard life is cramped. You will sleep in a small cabin. The boat might rock in heavy swells. Some people find this difficult for sleeping. It is part of the adventure.

Prices have risen since 2021. Diving in Thailand is more expensive now. You must budget for extra costs like tips. This is a reality of modern travel.

If you are new to currents, practice at /dive-sites/crystal-bay/ before heading to Richelieu Rock.