Koh Tachai: Diving, Snorkeling and Access Rules

Featured image: Pakpoomphoto, CC BY-SA 4.0, via Wikimedia Commons.

Can You Visit Koh Tachai? Access, Closure and Current Rules

Koh Tachai joined Similan Islands National Park in 1998. A Khao Lak dive center says the beach has been closed to tourists since October 2016. In May 2016, CNN quoted the head of Thailand's national parks department saying the island was closed "indefinitely". He cited litter and food waste, fuel leaking from tour boats, and coral damage. Visitor numbers reached almost 2,000 a day on some days. He said the island could take only a few hundred. None of the reporting we have seen says the beach has reopened, so plan on offshore activities only. Diving and snorkeling around the island have continued. There are no hotels on the island, and CNN put it about 137 km northwest of Phuket. Rules and access can change, so read the current notices from the Department of National Parks before you book.

Koh Tachai Pinnacle: What the Dive Is Like

Koh Tachai Pinnacle is a group of submerged granite boulders just off the island. Operators describe two pinnacles. The larger one in the south has a summit around 10 m down, with a mooring line to guide your descent. A smaller northern pinnacle tops out around 18 m. A sand patch at about 24 m links them, and the swim between them is roughly 50 m. Currents are often strong, which is why predators gather here. Guides suggest sheltering behind boulders and staying low near the bottom. Operators report giant trevally, bluefin trevally, dogtooth tuna, rainbow runner, chevron barracuda, marble grouper and batfish. Another dive center also lists a west wall, rocky bays and a gentle south reef. Mantas and whale sharks turn up occasionally, mostly January to May by operator accounts. Treat them as luck, not a promise. A typical dive here lasts about 50 minutes.

Snorkeling Koh Tachai: What to Expect

Snorkeling day trips run from the Khao Lak area, and a dive center states you can snorkel around the island. One operator lists turtles, parrotfish and snapper, matching the rest of the park. With the beach closed, expect to stay on the boat and in the water. Ask the operator two things before paying. First, find out whether the stop is the pinnacle or a sheltered reef. A summit around 10 m down sits well below the surface, and strong current is common there. Second, ask whether a guide stays in the water with the group. Pick a trip with a spotter boat and a floatation vest on offer if you are a weak swimmer.

Day Trip, Liveaboard or Skip It: Which Fits You

A day trip means roughly 1.5 hours each way by speedboat and two dives, if you are certified. A liveaboard gives more dives and early or late light on the pinnacle, but it costs more. Our recommendation is a day trip if you have a single free day, and a liveaboard if Tachai is the main reason you came. Skip both if you are neither a diver nor comfortable in open water.

Costs, Park Fee and What Is Included

Prices and hours checked November 2026 on one Khao Lak operator's page. Its Koh Tachai day trip with two dives and lunch is ฿5,400 per person. The national park fee is extra: ฿700 for foreigners and ฿300 for Thai nationals. A full gear set adds ฿500 and a dive computer adds ฿300 per day. A foreign diver renting everything pays ฿6,900 (฿5,400 + ฿700 + ฿500 + ฿300). Treat that as one operator's quote, not a market price. Liveaboard prices vary by boat and cabin, so request quotes directly.

• Base fare: ฿5,400 per person, includes dive insurance and VAT
• Park fee: ฿700 foreigners, ฿300 Thai nationals (excluded)
• Full gear rental: ฿500 (excluded)
• Dive computer: ฿300 per day
• Nitrox: ฿300 per tank
• Pickup outside the Khao Lak area, including Phuket: ฿500 per person

Getting There: Departure Point, Boat Time and a Typical Day

Day trips leave from Tub-lamu Pier near Khao Lak. One operator picks guests up from hotels between 06:30 and 07:30. Check-in is at 08:30 and the speedboat leaves at 09:00. Allow about 1.5 hours to reach the dive boat. Mooring up takes you to the first dive around 10:30. Lunch follows at 12:00, the second dive starts at 14:00, and the boat returns to the pier around 17:00. That is a long day, so pack sun protection and motion-sickness tablets. This operator rotates sites by weekday, and Saturday is its Koh Tachai day. Wednesday goes to Koh Bon. Ask which sites run on your date before you book.

Best Season and Conditions

Similan Islands National Park closes during the monsoon, as CNN noted in 2016. Opening and closing dates change, so take the current ones from the national park authority. Operators report manta and whale shark chances from January to May. Expect strong current on most days regardless of month. Water movement is what feeds the fish, so do not treat it as a defect.

Who Should Skip Koh Tachai

Newly certified divers and anyone uneasy with strong current should pick a calmer site first. Non-divers who dislike long boat rides should skip it too. Three mistakes catch people out. They assume they can land on the beach. They book a day when the boat goes elsewhere. They forget park fee and gear costs. Stay with your guide throughout and carry every scrap of litter back to the boat.

Nearby Dive Sites to Pair or Swap In

Koh Bon is the closest neighbor, and many itineraries combine it with Tachai. Our Koh Bon dive guide covers the swap. If Tachai is not running that day, browse the wider Similan dive site overview. Readers wanting a different profile can compare Elephant Head Rock, Similan Islands Guide. They can also read about Christmas Point. Another option is Donald Duck Bay, Similan Island 8: Snorkeling & Guide.