Koh Chang Diving Season: Best Months, Conditions & Trade-Offs

Featured image: Vyacheslav Argenberg, CC BY 4.0, via Wikimedia Commons.

Best Time to Dive Koh Chang: The Short Answer

Our pick for most divers is November to April. PADI gives November to April, Explore Koh Chang says November to May, and Chang Diving says October to May. Visibility figures differ as well. PADI reports 20–30 m in the dry season, Chang Diving about 10–20 m, and Explore Koh Chang at least 10 m, often more. We don't blend those into one number. Conditions shift by site and by week, so ask your dive center what the water looked like this week. Water temperature is steadier. PADI and Chang Diving both put it at 28–30°C (82–86°F).

Koh Chang Diving Season Month by Month

Diving Squad treats November to February as peak, with May to October as low season. Chang Diving counts October as the start of its main season. Use the table as a planning pattern, not a forecast.

Dry Season (Nov–Apr): What to Expect

Dry season gives the calmest seas and the best odds of long sightlines. Diving Squad notes daily air temperatures rarely fall below 30°C (86°F). Water sits at 28–30°C (82–86°F). From November to February you share boats and beaches with the most visitors. In high season, Chang Diving's boat leaves from Klong Prao Beach. Guests meet at the center around 8:00 AM or at the beach around 8:15 AM. March and April keep similar conditions with less booking pressure, which is why we like them for flexible travelers.

Monsoon Season (May–Oct): Is Diving Still Worth It?

Yes, on protected sites. Sources describe choppier water, lower visibility, fewer boats and reduced prices from May to October. Chang Diving frames it as fewer boats and more macro opportunities. Water stays near 28–30°C (82–86°F). We'd suggest this season for budget travelers, macro fans and course students. We'd skip it if you are a first-timer set on a wreck or Koh Rang, or if you get seasick on exposed crossings. Keep these mistakes in mind:

• Booking Koh Rang or a wreck dive with no weather-day buffer between May and October.
• Assuming one visibility number holds all year.
• Booking the cheapest low-season option without asking which sites actually run.

Which Dive Sites Work in Which Season

Distance drives exposure. Explore Koh Chang places the rocky sites about 3–5 km south and southwest of the island. Hin Luk Bat Dive Site, Koh Chang: Routes, Depth, Season is a pinnacle dropping to 20 m, per Diving Squad. HTMS Chang lies about 5 km off the coast, with its seabed at 30 m and main deck at 20 m. It was sunk in November 2012. For depth and access, see our HTMS Chang wreck guide. Koh Rang Marine Park is about an hour by boat. Offshore sites are the likeliest to be cancelled or rough in wet months, so treat them as a likelihood to discuss with your operator. Our full dive-site list covers the rest. When the sea is rough, this fallback pattern is common:

• Koh Rang, best on calm dry-season days. Our Koh Rang guide covers the trip.
• HTMS Chang wreck, about 5 km off.
• Near rocky pinnacles such as Hin Luk Bat and Hin Raab.
• Snorkel trip or a rest day.

Season by Diver Level and Goal

T11 lies at about 16 m, so Diving Squad calls it suitable for first-time wreck divers. HTMS Chang suits all qualified divers, with Advanced divers going deeper into the swim-throughs. Explore Koh Chang lists Open Water as 3–4 days with 4 boat dives, qualifying you to 18 m. You can read about the PADI Open Water course before choosing dates.

Marine Life and Whale Shark Expectations

PADI lists barracuda, moray eels, batfish and turtles as common sightings, and says marine life stays consistent through the year. Explore Koh Chang gives site depths of 8 to 30 m with a usual dive time of 1 hour. Whale sharks are another matter. Sources call them occasional, or "the odd" sighting. We wouldn't plan a trip month around one.

Costs, Crowds and Booking by Season

Prices checked November 2026. Chang Diving lists Fun Dives from ฿3,290 and the Open Water course from ฿14,490. Explore Koh Chang quotes Open Water at ฿15,000 to ฿16,000. Both say deals appear in quieter months, and Explore Koh Chang notes Koh Rang dives cost more because of the distance. Check the operator's own price page for the current rate. Explore Koh Chang also lists Koh Rang marine park fees. Divers pay ฿400 for adults and ฿200 for children. Snorkelers pay ฿200 and ฿100. Confirm those amounts with the national park authority before you budget. Our advice: pay for the sites you want, not the lowest sticker price.

Getting There and Dive-Day Logistics

PADI puts the Bangkok to Trat drive or bus at 4–5 hours, then a ferry of around 30–45 minutes. Dive centers cluster on the west coast, including Klong Prao and Bang Bao, and run boat transfers to the sites. Ferry timetables shift by season, so check the ferry company's current schedule.

Snorkeling in the Same Seasons

Snorkel trips follow the same weather. Explore Koh Chang lists snorkeling at ฿1,000 for a Koh Rang trip or a dive site off Koh Chang. Diving Squad describes full-day trips leaving Bang Bao around 09:30. Our Koh Chang snorkeling guide covers beach spots. Half-day speedboat trips visit Koh Wai, which has its own snorkeling page.

Questions to Ask Before You Book

Send these to your dive center before paying a deposit:

• Which sites are running this week?
• What is the weather cancellation or refund policy?
• How many divers per guide?
• Are Nitrox and wreck options available?
• Are marine park fees included?