Photo: Olga ga / Unsplash
Koh Chang
Koh Chang sits in the eastern Gulf of Thailand in Trat province, near the Cambodian border and about 5 hours by road from Bangkok. The headline dive is the HTMS Chang, a 100m ex-US Navy LST scuttled in 2012 and now Thailand's largest wreck, sitting upright from about 5m at the crow's nest to 30m on the sand. The rest is reef and boulder-pinnacle diving 3 to 5 km south and southwest of the island: Hin Luk Bat, Hin Raab and the Koh Rang National Park sites, with soft corals, swim-throughs, morays, blue-spotted rays and the occasional turtle. This is not big-pelagic pinnacle diving; topography is gentle and most sites are shallow, 5 to 25m. The season runs roughly October to May, with November to April the calmest window. Visibility is modest and variable here, commonly 5 to 15m and plankton- and runoff-dependent, better on the best dry-season days. The southwest monsoon from June to September brings rain, choppy seas and trip cancellations. Most diving is budget land-based day-trips from the island.
What makes it special
- HTMS Chang: a 100m ex-USS Lincoln County (LST-898) tank landing ship scuttled in 2012, Thailand's largest wreck, upright from ~5m to 30m and diveable across certification levels
- Shallow reef and boulder-pinnacle sites (Hin Luk Bat, Hin Raab) with soft corals, swim-throughs, morays and blue-spotted rays, most within 5 to 25m
- Koh Rang National Park sites (Three Finger Reef, Koh Rang pinnacle) with harder coral gardens and a chance of turtles and larger fish
- Cheap, low-friction land-based diving reachable from Bangkok without a liveaboard
Price range
$
Trip length
1–4 days
Diver level
Open water
Trip type
Day trip, Land based
Price is per person for a typical trip, excluding international flights ($ = under $2,000).
Budget land-based day-trip diving. A two-dive day trip typically runs about 2,500 to 3,500 baht (roughly $70 to $100), gear included; HTMS Chang wreck trips sit at the higher end. A Mu Ko Chang / Koh Rang National Park fee applies at the marine-park sites, usually not included in advertised prices - typically ~400 baht for foreign-adult divers at Koh Rang (200 baht is the snorkeler rate). No liveaboard here; costs are far below the Andaman.
Best time to dive
- Current
- Mild
- Water temp
- 27–31°C (coldest Jan, warmest Apr)
- Visibility
- 5–20m — Modest and variable for the eastern Gulf: commonly 5 to 15m and plankton- and runoff-dependent. Best dry-season days (November to April) can reach 20m and occasionally more, but the higher figures operators quote are best-case, not typical. Drops to roughly 3 to 10m in the June to September monsoon and after heavy rain.
- Getting there
- Moderate — Reachable but with some friction: 1 domestic flight.
- Experience
- Most reef and pinnacle sites suit all levels, including Open Water, with mild currents and shallow profiles. Open Water divers can dive the upper decks of the HTMS Chang to about 18m, but the deck at ~20 to 23m and the sandy bottom at 30m need Advanced Open Water or Deep/Wreck training; full interior penetration requires specific overhead-environment certification. The Koh Rang pinnacle (Hin Ga Daeng) can have stronger, less predictable current.
Nearest airports
- TDX — Trat Airport (Domestic Bangkok Airways flights from Bangkok (BKK/DMK), about 1 hour; roughly 20 minutes by road to the Laem Ngop ferry piers)
- BKK — Suvarnabhumi Airport (Bangkok) (Nearest major international airport; connect to a domestic flight to Trat (TDX) or take a bus/minivan roughly 4 to 5 hours to the ferry piers)
Permit required
Sites within Mu Ko Chang / Koh Rang National Park require a national-park entrance fee, payable by divers and snorkellers on trips to Koh Rang and nearby islands. Full wreck penetration on the HTMS Chang requires appropriate technical/wreck certification.
Mu Ko Chang / Koh Rang National Park fee: foreign divers pay ~400 baht adult / 200 baht child at Koh Rang (double the 200/100 baht snorkeler rate); Thai nationals 40/20 baht; not included in advertised dive-trip prices.
Marine life
Sightings are never guaranteed — the bars show typical likelihood by month.
| Month | Likelihood |
|---|---|
| January | rare |
| February | rare |
| March | rare |
| April | rare |
| May | rare |
| June | rare |
| July | rare |
| August | rare |
| September | rare |
| October | rare |
| November | rare |
| December | rare |
Whale sharks are reported occasionally, sometimes tied to plankton-rich water, but sightings at Koh Chang are genuinely rare and never reliable despite operator marketing.
| Month | Likelihood |
|---|---|
| January | commonly seen |
| February | commonly seen |
| March | commonly seen |
| April | commonly seen |
| May | commonly seen |
| June | commonly seen |
| July | commonly seen |
| August | commonly seen |
| September | commonly seen |
| October | commonly seen |
| November | commonly seen |
| December | commonly seen |
Blue-spotted rays and other stingrays are commonly seen on the sandy patches at Hin Raab and the National Park reefs.
| Month | Likelihood |
|---|---|
| January | commonly seen |
| February | commonly seen |
| March | commonly seen |
| April | commonly seen |
| May | commonly seen |
| June | commonly seen |
| July | commonly seen |
| August | commonly seen |
| September | commonly seen |
| October | commonly seen |
| November | commonly seen |
| December | commonly seen |
Moray eels are common in the boulders and wreck recesses across Hin Luk Bat, Hin Raab and the HTMS Chang.
| Month | Likelihood |
|---|---|
| January | commonly seen |
| February | commonly seen |
| March | commonly seen |
| April | commonly seen |
| May | commonly seen |
| June | commonly seen |
| July | commonly seen |
| August | commonly seen |
| September | commonly seen |
| October | commonly seen |
| November | commonly seen |
| December | commonly seen |
Barracuda are reliable around the HTMS Chang and the rocky reefs, sometimes in schools.
| Month | Likelihood |
|---|---|
| January | commonly seen |
| February | commonly seen |
| March | commonly seen |
| April | commonly seen |
| May | commonly seen |
| June | commonly seen |
| July | commonly seen |
| August | commonly seen |
| September | commonly seen |
| October | commonly seen |
| November | commonly seen |
| December | commonly seen |
Anemonefish (clownfish) occupy anemone fields on the shallow reefs, notably at Hin Luk Bat.
| Month | Likelihood |
|---|---|
| January | commonly seen |
| February | commonly seen |
| March | commonly seen |
| April | commonly seen |
| May | commonly seen |
| June | commonly seen |
| July | commonly seen |
| August | commonly seen |
| September | commonly seen |
| October | commonly seen |
| November | commonly seen |
| December | commonly seen |
Batfish are among the resident schooling fish on the HTMS Chang wreck.
| Month | Likelihood |
|---|---|
| January | commonly seen |
| February | commonly seen |
| March | commonly seen |
| April | commonly seen |
| May | commonly seen |
| June | commonly seen |
| July | commonly seen |
| August | commonly seen |
| September | commonly seen |
| October | commonly seen |
| November | commonly seen |
| December | commonly seen |
Snappers and fusiliers school over the reefs at Hin Luk Bat and Hin Raab.
| Month | Likelihood |
|---|---|
| January | occasional |
| February | occasional |
| March | occasional |
| April | occasional |
| May | occasional |
| June | occasional |
| July | occasional |
| August | occasional |
| September | occasional |
| October | occasional |
| November | occasional |
| December | occasional |
Turtles are seen occasionally, most often on the Koh Rang National Park reefs; not guaranteed on any dive.
| Month | Likelihood |
|---|---|
| January | commonly seen |
| February | commonly seen |
| March | commonly seen |
| April | commonly seen |
| May | commonly seen |
| June | commonly seen |
| July | commonly seen |
| August | commonly seen |
| September | commonly seen |
| October | commonly seen |
| November | commonly seen |
| December | commonly seen |
Nudibranchs are common macro subjects across the reefs and on the wreck structure.
| Month | Likelihood |
|---|---|
| January | occasional |
| February | occasional |
| March | occasional |
| April | occasional |
| May | occasional |
| June | occasional |
| July | occasional |
| August | occasional |
| September | occasional |
| October | occasional |
| November | occasional |
| December | occasional |
Seahorses are found on the reefs and wreck but are small and easily missed; a spotter helps.
| Month | Likelihood |
|---|---|
| January | commonly seen |
| February | commonly seen |
| March | commonly seen |
| April | commonly seen |
| May | commonly seen |
| June | commonly seen |
| July | commonly seen |
| August | commonly seen |
| September | commonly seen |
| October | commonly seen |
| November | commonly seen |
| December | commonly seen |
Soft corals cover the boulder reefs and pinnacles and encrust the HTMS Chang; the dominant reef-building character here rather than extensive hard-coral gardens.
Dive sites
Worth knowing before you book
- Visibility is modest and inconsistent: often 5 to 15m and plankton/runoff dependent; the up-to-30m figures are best-day, dry-season exceptions, not the norm.
- The June to September southwest monsoon brings rain, choppy seas, poorer visibility and frequent trip cancellations.
- This is not big-pelagic pinnacle diving: gentle topography, soft corals and small critters, with none of the reliable manta/hammerhead action of other destinations.
- Whale sharks and 'reef sharks' appear in operator marketing but sightings are genuinely rare and never reliable here.
- Boat rides of roughly 30 to 90 minutes reach most sites, and Koh Rang park fees are usually charged on top of the advertised price.
Sources & last checked
Checked July 2026
This is a researched draft, not yet human-verified. The seasonality and logistics are drawn from the sources below — confirm specifics (permits, fees, closures) with an operator before you book.
- HTMS Chang — Wikipedia
- USS Lincoln County (LST-898) — Wikipedia
- Mu Koh Chang National Park to charge diving and snorkelling fees — Bangkok Post
- Best Dive Sites in Koh Chang — BB Divers Koh Chang
- What is the Best Time for Diving in Koh Chang? — Diving Koh Chang
- HTMS Chang Wreck – Thailand's Largest Shipwreck — Chang Diving
- Diving in Koh Chang — PADI
- Sea water temperature Ko Chang — seatemperature.info
- How to get from Trat Airport to Koh Chang. Transport guide and prices — Trat Airport Guide
- Koh Chang Ferry passenger information and timetables — Koh Chang Ferries
Note on the data: Seasonality and visibility rest largely on dive-operator and tourism pages (bbdivers, changdiving, diving-kohchang), coded conservatively; visibility deliberately kept honest rather than repeating best-day 30m figures. Water temperatures are from consumer sea-temperature aggregators, not a primary oceanographic source, and are interpolated into small monthly bands. Site coordinates are approximate island/area positions, not surveyed dive-site GPS. HTMS Chang history and the park fee are corroborated by Wikipedia and Bangkok Post respectively. Confidence medium. Water temperature: Warm and stable year-round, roughly 27 to 31°C; monthly min/max are a small band interpolated around published monthly average surface temperatures (coolest Dec to Feb, warmest Apr to May). A 3mm wetsuit is generally enough. Access: From Bangkok, either fly ~1 hour to Trat (TDX) then ~20 minutes by road to the Laem Ngop piers, or take a bus/minivan ~4 to 5 hours; the car ferry crossing takes about 30 minutes and runs roughly every 45 minutes, with total door-to-hotel time from Trat airport about 2 to 2.5 hours.