Snorkeling, Diving and Island Hopping from Koh Chang

At a glance

The reefs are offshore, so the snorkelling is a boat trip or it is nothing

Every mapped snorkel and dive site around Koh Chang sits offshore. The nearest are granite pinnacles 30 to 40 minutes out by boat; the sheltered bays that shared trips actually visit are in the Koh Rang group, a good deal further. Koh Chang's own west coast shelves out over sand and stone. You cannot walk into the sea from your beach and find a reef, and no local operator pretends otherwise — every snorkelling product on the island is sold as a boat day leaving Bang Bao.

Mu Ko Chang National Park covers about 650 km² and 52 islands. Koh Rang is the outer cluster: a ranger station, a couple of bungalows, a passable restaurant, toilets and a camping area. You can book a night there from Koh Chang, though people staying is a rarity. What makes it the destination is geography rather than spectacle. The bays are sheltered and shallow enough to snorkel, and the water is clearer than anything closer in.

Two points of confusion are worth clearing up before you book.

First, Mu Ko Chang does not close for the monsoon. The famous 16 May to 14 October shutdown belongs to the Andaman parks — Similan, Surin, the Mu Ko Lanta sites. Gulf-side Ang Thong and Mu Ko Chumphon close 1 November to 15 December, which is the opposite window. Mu Ko Chang is listed as open, year round, around the clock. What stops in the low season is the boat services, and those dates are specific and published — see the tables below, and Chapter 3 for the weather behind them.

Second, the park's own status list has loose ends nobody has tidied. A Tourism Authority list dating from 2023 shows three islands in the Koh Rang group — Ko Thong Lang, Ko Kra and Ko Thian — as closed until further notice on account of coral damage, while dive operators still publish Koh Kra and Koh Tien as active sites. Separately, in May 2024 the national parks department closed twelve marine parks after bleaching surveys, Mu Ko Chang among them, and no reopening announcement for Trat could be found. Neither loose end can be settled from published sources. Ask your operator which islands they are permitted to stop at this month — they run the route weekly and the rangers turn boats away, so the answer is worth more than a list. If you want it from the park itself, the office number is 039 510 928, and a Thai speaker helps.

A full-day boat trip is eight or nine hours and puts you in the water for two or three

Koh Rang is well over an hour out from Bang Bao on a wooden boat, and you have to come back. Operators stop for 45 to 60 minutes at each of three or four islands. Add lunch and the beach pickups and you have a long day with a couple of hours of snorkelling inside it.

The standard four-island and five-island trips run into the Koh Rang archipelago: Koh Yak Yai, Koh Yak Lek, Koh Mapring, the beach at Koh Rang itself, and Monkey Rock. Some four-island versions swap the last stop for Koh Wai. A separate three-island trip runs north instead, to Koh Wai, Koh Klum and Koh Laoya, and starts later — out around 10:30, back about 16:00.

Slow boat. Converted wooden fishing boats, repainted, leaving Bang Bao between 09:00 and 09:30 and back at the pier between 16:00 and 17:30. Some carry over a hundred people. 750–900 THB per person, with hotel transfer, mask and snorkel, lunch and drinks included. Fins are usually extra, around 100 THB (about US$3). The large purpose-built vessel Thaifun sits above the rest at 1,490–1,500 THB (about US$45).

Speedboat. Cuts the transit substantially and makes half-days possible: 09:00–12:30 or 13:00–16:30, for around 1,000 THB (about US$30). A full speedboat day runs about 1,200 THB (about US$36).

The wooden boat is a day on a boat that includes snorkelling; the speedboat is a snorkelling trip. For two people, or for anyone who has snorkelled a better reef, a boat carrying over a hundred passengers is not worth nine hours to spend two of them in the water: take the speedboat half day at about 1,000 THB, or give the day to the island instead. The wooden boat earns its 750–900 THB for a group that wants a day out on the water, and for anyone whose budget decides it. If you are prone to seasickness, note that the slow boat is where you will spend three hours in whatever swell is running, and that a speedboat half-day gets you off the water before the afternoon wind builds.

For four or more people, a private charter starts to make arithmetic sense: 6,000–10,000 THB (about US$180–300) a day for a wooden boat, 6,500–15,000 THB for a speedboat. One published example puts a private speedboat four-island day at 9,500 THB for one to seven passengers, 11,000 THB for eight to ten and 13,000 THB for eleven to thirteen. That buys you the itinerary and, more usefully, the timing — you leave the crowded bay when you want to.

Koh Wai is a half day, Koh Mak is a full day, Koh Kood is an overnight

The three islands south-east of Koh Chang are routinely sold as interchangeable day trips. They are not, and the timetables are what decide it.

Koh Wai is 15 to 30 minutes out and works cleanly as a half day. Bangbao Boat sells a Koh Wai trip at 500 THB (about US$15) per person including pier transfers, snorkel gear and a 50 THB food voucher at Pakarang Resort. The boat leaves Bang Bao around 09:30, drops you at 10:15–10:30 and collects at about 13:00 — two and a half to three hours ashore. The scheduled speedboats also allow a same-day return. That half day is the whole product, which tells you roughly how much island there is.

Koh Mak works as a full day. It is 30 minutes by speedboat or up to two hours on a wooden boat, and an early sailing leaves you roughly three to four hours ashore before you have to be back at the pier. That figure comes from traveller reports rather than an operator schedule, so build in a margin and confirm your return sailing before you walk away from the jetty.

Koh Kood does not work as a day trip. It is about 30 km out and the crossing is one to three hours depending on the boat. The scheduled timetables leave effectively no time on the island: the Boonsiri catamaran reaches Ao Salad at 10:30 and the return sailing leaves at 11:00. Doing Koh Kood and back in a day means chartering a private speedboat, which is quoted at roughly 15,000 THB (about US$455). Give it a night, or two.

Scheduled inter-island boats

Return sailings from Koh Kood: Koh Chang Express 11:30 and 14:30; Kai Bae Huts 11:00; Boonsiri 11:00 and 14:30. Koh Mak to Koh Kood is 500 THB on Koh Chang Express, 400 THB on Boonsiri.

In the boat-service high season, 1 November to 30 April, wooden boats and speedboats add capacity out of Bang Bao at published fares: wooden boat 400 THB to Koh Wai, 500 THB to Koh Mak, 700 THB (about US$21) to Koh Kood; speedboat 900 THB to Koh Mak, 1,200 THB to Koh Kood. That window is a different thing from the tourism high season, which runs November to March and is dearest from late November to February — see Chapter 3. Those services stop at the end of April or in early May depending on demand and weather. Boonsiri is the only operator that carries on through the wet months, and even that drops to a single afternoon boat from June to September.

Every fare and time above is from the 2025/26 season, plus the published 2026 low-season reductions. The 2026/27 timetable, from 1 November 2026, had not been issued when this was written. Treat these as the shape of the service rather than a booking.

Diving here is one big wreck and a set of shallow pinnacles

The headline dive is the HTMS Chang: a 100-metre ex-US Navy transport scuttled by the Royal Thai Navy in November 2012 about 5 km off the island as an artificial reef. It is Thailand's largest diveable wreck, it sits upright, and the seabed is at 30 metres. The top of the stern tower is at about 7 metres, which is what makes it accessible to more than just deep-certified divers.

Certification maps onto the wreck in three bands. Open Water divers can work the tower and the above-deck structure. Advanced Open Water, or equivalent, is needed for the main deck and the deeper sections. Going inside requires wreck training — local shops run TDI Advanced Wreck courses from around 18,990 THB (about US$575). Published deck depths disagree: one local guide says 20 metres, an operator says 24, another guide says 25. The 30-metre seabed and the 7-metre tower top are consistent everywhere, so plan against those and ask your shop for their own deck figure.

Everything else is shallow. The local sites, 30 to 40 minutes out, are Hin Luk Bat at 17–20 m (a pinnacle with the healthiest coral in the local set and big schools of fish), Hin Rap at 15–16 m, Hin Nam Tai "Blueberry Hill" at 12 m, Hin Rua Tek "Banana Rock" at 15 m, Koh Khlum at 8–12 m and the small T11 wreck at 13–15 m. The marine park sites out at Koh Rang, about an hour and a half away, run to Hin Ga Daeng (Koh Rang Pinnacle) at 26 m, Hin Kuak Ma (Three Finger Reef) at 15 m, Koh Yak at 15 m, Koh Laun at 14 m, Koh Mapring at 10–12 m and Koh Tien West at 13–15 m, the last of which was flattened by storms and bleaching and is described by operators as starting to recover.

Shallow, warm and current-free is a poor recipe for dramatic diving and an excellent one for learning. Water sits at 28–30°C all year. Two fun dives run 3,300–3,500 THB (about US$100–106). Discover Scuba is 5,000–5,500 THB (about US$150–165), or around 3,000 THB for a single beach dive. Open Water is 13,000–16,000 THB (about US$395–485) and Advanced Open Water 13,490–14,500 THB. A night dive is 2,500 THB (about US$76); a package pairing the HTMS Chang with a night dive is 5,000 THB. Multi-dive packages run to 8,500 THB for six dives and 11,000 THB (about US$333) for ten. Prices include hotel transfer, kit, guide and lunch. The park fee is not included, and divers entering the Koh Rang area pay 400 THB (about US$12) rather than the snorkeller's 200 THB. The child diver fee is published as 200 THB by one guide and 300 THB by one operator's own price list, so ask when you book.

The established shops are BB Divers (running since about 2003, bases at White Sand Beach and Bang Bao pier), Koh Chang Divers (Bang Bao, small and British-run), Chang Diving Center (Klong Prao, with nitrox and technical and wreck training), Local Divers, Scuba Squad and Thai Ocean Academy. The dive season is November to May. Shops largely stay open through the rains and go out daily when conditions allow, because there are sheltered moorings to dive from. Whale sharks are a January-to-April possibility, not an expectation.

The coral is mediocre, and it compares badly with the Andaman

Koh Rang's coral is patchy, a good deal of it is dead and sun-bleached, and there are stretches where you are swimming over rubble and sea urchins. Recurring visitor assessments are consistent about it: mediocre with occasional interesting fish but still fair value; most if not all the coral dead; not impressive compared with Egypt or Australia. The fish life is rated better than the coral by almost everyone who writes about it, and large schools are the thing people remember.

The 2024 bleaching event was real and local. Surveys run between 2 April and 8 May 2024 recorded bleaching of 10 to 70 per cent depending on the site , with Thai sea temperatures averaging 31–32.8°C during the survey period, and the national parks department closed twelve marine parks including Mu Ko Chang as a result.

On visibility, the comparison is not close. Koh Chang averages 10 to 15 metres in season, with individual sites as low as 5. Published comparisons put the Similans at about 20 metres as a norm, with exceptional days beyond 40, and the wider Andaman coast at up to 30. A Koh Chang dive operator's own Gulf-versus-Andaman comparison page sells the Gulf on calm water, mild currents and the absence of crowds rather than on clarity.

There is a real counterweight, and it is a timing one. The Andaman marine parks shut entirely from mid-May to mid-October, while Koh Chang dives year round from sheltered moorings. Almost no other boats are on the sites in those months. If your trip falls in June, this is the better coast, whatever the visibility numbers say.

So: if you have snorkelled the Similans or the Red Sea, Koh Rang will disappoint you, and one boat day is enough — make it the speedboat half day rather than nine hours on the slow boat. If this is your first tropical snorkel, or you are travelling with children who want warm, shallow, sheltered water with plenty of fish in it, it does the job well.

Booking: what you pay, what you pay on top, and what to bring

Shared trips are booked through your resort, a beach tour desk or the operator directly, usually the day before. The fare bands above are per person and cover the boat, the beach pickup, mask and snorkel, lunch and water, tea or coffee. Fins are commonly an extra 100 THB. The marine park fee is always extra and always cash, handed over on the water.

Pickups run north to south and the boat waits for nobody: roughly 08:00 at White Sand Beach, 08:15 at Klong Prao, 08:30 at Kai Bae and 08:45 at Lonely Beach, with the boat leaving Bang Bao between 09:00 and 09:30 and dropping you back at your resort around 17:30. Bang Bao is at the far south-western end of the island, so the further north you have chosen to sleep, the earlier your day starts — see Chapter 2 on where the beaches sit relative to the pier.

Low season closes specific operators on specific dates rather than shutting the island down. Kai Bae Huts speedboat trips close from May to October. Permpoon Sub is listed as closed from 16 May 2026 to early November. Thaifun and Sattra Tours keep running but describe themselves as weather dependent in the rainy season, as does Mr Khai's four-island trip. In practice, from May onward, book one day ahead and expect a cancellation call if the sea is up.

What to bring: cash for the park fee, fins and drinks, since card payment is not something to count on out there. A rash vest or t-shirt matters more than sunscreen when you are going to spend an hour face-down in the sun. A dry bag, a towel of your own, and motion-sickness tablets if you have booked the wooden boat. Your certification card if you are diving. Draw money before you travel to the pier — Chapter 7 covers where the ATMs are and are not.

Keep reading

• Boat trips collect from the beaches at 08:00–08:45, so the morning after you land is the first one you can use: book a fixed-price transfer to the mainland ferry pier. The ferry crossing and the island leg beyond it are your own arrangement.

Last updated: 2026-08-29. Ferry and pier notes come from Smile Taxi Service drivers running Bangkok-Trat transfers.