Thailand – Pattaya & Koh Chang

The eastern shore of the Gulf of Thailand is the closest diving to Bangkok. Off Pattaya the Thai Navy has scuttled several retired WWII-era landing ships as artificial reefs (Khram, Kut, Mataphon), and the near and far islands offer shallow coral slopes that are used heavily for training. Further south, the Samae San islands near Sattahip add the WWII freighter Hardeep and clearer, current-swept sites inside a navy-administered area. Some 250 km to the south-east, the Koh Chang archipelago in Trat province is part of Mu Ko Chang National Park: boats from Bang Bao, Koh Mak and Koh Kood dive the HTMS Chang wreck (sunk in 2012), the pinnacles south of Koh Chang and the reefs around Koh Rang. Visibility is modest compared with the Andaman Sea, but the water is warm and the wrecks are rich in fish life.

Facts

Best season: Pattaya is dived year-round; calmest and clearest roughly November to early April, with south-west storms possible from late October. Koh Chang/Koh Kood: best mid-October to May; in the June–mid-October green season trips run when weather and numbers allow, and HTMS Chang trips are mainly a high-season offer – check current schedules
Water temperature: Warm all year: around 28–30 °C, rarely below 29 °C off Pattaya
Visibility: Pattaya wrecks and near islands often 5–15 m (sometimes only ~5 m on the Kut); far islands and Samae San can reach 15–20 m; plankton blooms in March–April reduce it
Getting there: Pattaya is about 150 km from Bangkok (bus ~2.5 h depending on traffic); boats leave from Pattaya (Bali Hai) and, for Samae San, from the Samae San fishing pier. Koh Chang: Bangkok Airways to Trat (TDX), then ~20 km to Ao Thammachat pier and a ~30-minute car ferry (Centrepoint pier is the slower alternative); last ferries around 19:00 – check current timetables
Park fees: Mu Ko Chang National Park lists 200 THB per foreign adult (100 THB child). Koh Rang dive trips: Koh Kood Divers collects 400 THB per diver per day in cash on the boat. Some Pattaya day-trip prices include marine park fees – check current fees
Samae San & navy areas: The Samae San islands are administered by the Royal Thai Navy and access is limited; the area is used by the navy, so extra restrictions may apply, and the north beach of Koh Chuang is closed to scuba. Koh Phai's beaches are also navy-restricted. Dive only with an operator that runs regular Samae San trips – check current rules
Koh Rang closures: No seasonal closure of Koh Rang was found in park or operator sources (the park lists itself as open all year); operators run Koh Rang on set weekdays in high season and on demand in the green season – check current status

Season

Best months: Feb, Mar, Apr, May, Jun, Jul, Aug, Sep
Acceptable: Jan, Oct
Poor: Nov, Dec
Water temperature: 27–30 °C

The Gulf of Thailand is best from February to September. The northeast monsoon brings the worst weather in November and December, with visibility sometimes under 5 m. Whale sharks are most often seen March to May (Chumphon Pinnacle, Sail Rock).

Dive sites (49)

Koh Kood & Koh Mak

Ao Karang – intermediate
Ao Kluai – intermediate
Ao Yai Koet – intermediate
Bang Bao Reef (Koh Kood) – beginner
Hin Ao Salad – 14 m, beginner
Hin Ao Yai – intermediate
Hin Loy – 16 m, intermediate
Hin Yedhi & Ao Tum – 4–14 m, beginner
Klong Hin Reef (Anemone Bay) – 12 m, intermediate
Koh Maisi Lek & Soneva Reef – intermediate
Koh Phe – 15 m, beginner
Koh Raet (Koh Kood) – 4–14 m, beginner
Tui Reef – intermediate

Koh Chang (south & HTMS Chang)

Blueberry Hill – 5–16 m, beginner
Hin Luk Bat – 5–25 m, beginner
Hin Raab South – 3–16 m, beginner
Hin Rua Taek – 3–16 m, beginner
Hin Sam Sao – 16 m, beginner
HTMS Chang – 5–32 m, advanced
Koh Khlum – 3–10 m, beginner
Koh Wai – 2–12 m, beginner
T11 Wreck – 10–16 m, beginner

Samae San & Sattahip

Hardeep Wreck – 18–30 m, advanced
Hin Chalam – 5–25 m, intermediate
Hin Yai Pinnacle – 14–30 m, intermediate
Koh Chan – 3–18 m, beginner
Koh Chuang – 5–18 m, beginner
Koh Ron (Koh Rong Khon & Koh Rong Nang) – 25 m, beginner
Petchburi Bremen Wreck – 15–24 m, advanced
Samaesan Hole – 85–100 m, advanced
Shark Fin Rock – 28 m, intermediate
Sharkfin Deep Drop (Samaesan Cliff) – 50–86 m, advanced
T-Wrecks (T.94 & T.95) – 18–25 m, intermediate

Mu Ko Chang NP – Koh Rang

Hin Ga Daeng – 5–30 m, advanced
Koh Thian West – 3–16 m, beginner
Koh Tong Lang & Koh Kra – 2–12 m, beginner
Koh Yak & Koh Laun – 3–12 m, beginner
Three Finger Reef – 5–20 m, beginner

Pattaya Far Islands

HTMS Khram – 12–30 m, advanced
Koh Hu Chang (Elephant Ears Rock) – 15 m, beginner
Koh Klung Badan – 5–22 m, intermediate
Koh Man Wichai – 3–22 m, intermediate
Koh Phai – 3–18 m, beginner
Koh Rin & Koh Rin Rocks – 3–22 m, intermediate

Pattaya Near Islands

HTMS Kut – 12–30 m, advanced
HTMS Mataphon – 12–23 m, intermediate
Koh Khrok – 5–12 m, beginner
Koh Larn South (Laem Tong & South Point) – 3–22 m, beginner
Koh Sak – 3–30 m, beginner

Operators (9)

Seafari Dive Centre Pattaya – dive centre, Pattaya (Mikes Mall, Pattaya 2nd Road)
Pattaya Dive Centre – dive centre, Pattaya Beach Road (Tipp Plaza)
Pattaya Scuba Adventures – dive centre, Pattaya (Soi 15, 2nd Road)
BB Divers Koh Chang – dive centre, Bang Bao pier, Koh Chang
BB Divers Koh Kood – dive centre, Koh Kood (Siam Beach Resort area)
Koh Chang Divers – dive centre, Bang Bao Plaza, Koh Chang
Koh Kood Divers – dive centre, Klong Chao, Koh Kood
Koh Mak Divers – dive centre, Koh Mak
The Scuba Squad – dive centre, Bang Bao pier car park, Koh Chang

Routes (6)

Site positions are approximate unless marked otherwise and are for orientation only — never for navigation. Several wrecks lie at 25–32 m and many sites have strong tidal currents; park fees, navy-area rules and schedules change, so confirm them with your dive centre.