Southeast Asia · Vietnam
Côn Đảo
One of Vietnam's last dugong refuges with protected turtle nesting beaches
Photo: Tycho · CC BY-SA 3.0
An isolated archipelago roughly 80 kilometers off Vietnam's southern coast, Côn Đảo protects one of the country's last dugong populations along with important green turtle nesting beaches inside its national marine park. Coral reefs here are healthier and less crowded than mainland Vietnam sites, though the area remains lightly developed for diving with a short weather window between the two monsoon seasons. Dugong sightings are rare and never guaranteed on any given dive.
About diving in Côn Đảo
The dive scene is small and shaped by the national park. A handful of operators work out of Con Son town, boats leave for a two-dive day with a beach or island stop in between, and park entry and any landing permits for the outer islets are arranged by the operator rather than by you. Wind direction, not a site list, decides where you end up: crews move between the sheltered and exposed sides of the group as the season turns, and a day can be called off outright when swell wraps around the islands.
Diving is shallow and unhurried. Fringing reef runs off the islets in broad hard-coral gardens that slope gently into sand, rock and seagrass, and dives within 25 metres can run long on a single tank. The exposed sides have boulder shorelines with more structure and more water movement, but nothing here is a wall; the interest is coral cover and the animals grazing it. Visibility moves with the season and with plankton, and rarely holds steady across a whole week.
It rewards divers content with a short site list and thin support on land. A cancelled boat costs a whole day out of an already narrow window, rental gear runs to limited sizes, and there is no recompression facility on the island. Most people fold diving into a wider trip, since the prison museums and Hang Duong cemetery draw much of the island's visitor traffic and the park's turtle programme is an evening out in its own right. It is quiet, shallow and low-pressure, and wrong for anyone chasing depth, current or a guaranteed headline animal.
Best time to dive Côn Đảo
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Season | Off-season | Fair | Fair | Good | Good | Prime | Prime | Prime | Good | Fair | Off-season | Off-season |
| Sea surface | 26°C79°F | 26°C79°F | 27°C81°F | 29°C84°F | 30°C86°F | 30°C86°F | 29°C84°F | 29°C84°F | 29°C84°F | 29°C84°F | 28°C82°F | 27°C81°F |
| Daytime high | 26°C79°F | 26°C79°F | 28°C82°F | 30°C86°F | 30°C86°F | 30°C86°F | 30°C86°F | 30°C86°F | 29°C84°F | 29°C84°F | 29°C84°F | 28°C82°F |
| Rain | 26 mm1.0 in | 9 mm0.4 in | 32 mm1.3 in | 62 mm2.4 in | 169 mm6.7 in | 194 mm7.6 in | 231 mm9.1 in | 184 mm7.2 in | 278 mm10.9 in | 247 mm9.7 in | 208 mm8.2 in | 73 mm2.9 in |
| Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|
| Off-season | Fair | Fair | Good | Good | Prime |
| Sea surface | |||||
| 26°C79°F | 26°C79°F | 27°C81°F | 29°C84°F | 30°C86°F | 30°C86°F |
| Daytime high | |||||
| 26°C79°F | 26°C79°F | 28°C82°F | 30°C86°F | 30°C86°F | 30°C86°F |
| Rain | |||||
| 26 mm1.0 in | 9 mm0.4 in | 32 mm1.3 in | 62 mm2.4 in | 169 mm6.7 in | 194 mm7.6 in |
| Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|
| Prime | Prime | Good | Fair | Off-season | Off-season |
| Sea surface | |||||
| 29°C84°F | 29°C84°F | 29°C84°F | 29°C84°F | 28°C82°F | 27°C81°F |
| Daytime high | |||||
| 30°C86°F | 30°C86°F | 29°C84°F | 29°C84°F | 29°C84°F | 28°C82°F |
| Rain | |||||
| 231 mm9.1 in | 184 mm7.2 in | 278 mm10.9 in | 247 mm9.7 in | 208 mm8.2 in | 73 mm2.9 in |
2011–2025 averages. Sea surface: NOAA Coral Reef Watch, measured at the surface, so deeper water can run colder. Daytime high and rain: NASA POWER.
Northeast monsoon swell limits diving November-January; calmest seas and best visibility run June-August.
Best months: June, July, August
Côn Đảo water temperature and weather by month
The sea surface runs from 26 °C (79 °F) in January to 30 °C (86 °F) in May. Most rain falls from May to November, peaking at about 280 mm (11 in) in September; it stays largely dry from December to April. Daytime highs reach 30 °C (86 °F) in May and drop to 26 °C (79 °F) in January. The coldest water here is about 26 °C (79 °F), so pack a 3 mm full suit.
Dive types & marine life
Green turtles are the dependable sighting, with nesting on the park's beaches through the calm June-to-August window, when rangers run guided night watches. Reef days bring groupers, barracuda and trevally over the coral gardens, plus nudibranchs, cuttlefish and octopus in the rubble. Dugong browse seagrass beds away from the usual dive sites, so an encounter is incidental rather than planned.
- Reef
- Coral garden
- Muck & macro
- Dugongs & manatees
- Sea turtles
- Barracuda
- Trevally & jacks
- Groupers
- Nudibranchs
- Octopus & cuttlefish
- Reef fish swarms
- Pristine corals
Best dive sites in Côn Đảo
Reef
Horseshoe reef beside Con Dao's main turtle nesting island
Reef
Shark Fin's shallow coral gardens and nudibranch zones
Reef
Close-in reef of nudibranchs, batfish and giant pufferfish
Reef
Western Con Dao reef spanning 4 to 25 m
Ong Dung Bay
Sheltered fringing reef close to the main town
How to get to Côn Đảo
Most divers fly from Ho Chi Minh City to the island's small airport; fast ferries also run from Vung Tau and from Tran De in the Mekong Delta when seas allow. Con Son town is the only practical base, with the main pier a short drive away. Diving is by day boat with a few easy shore entries, and operators are few enough that booking ahead matters.
Photos from Côn Đảo
Tycho · CC BY-SA 3.0
Dieter Hug · CC BY 3.0
Dive videos
DIVING IN VIETNAM - CON DAO ISLAND · Organic Reef Rehabilitation Center on YouTube
Photo credits
- Rocky shoreline and forested hills along Con Son Island's coast in the Con Dao archipelago, Vietnam. by Tycho, CC BY-SA 3.0, via Wikimedia Commons
- Small fishing boat resting on a quiet beach edged by pine trees in Con Dao National Park. by Tycho, CC BY-SA 3.0, via Wikimedia Commons
- A water buffalo and its handler cross a quiet beach at dusk in the Con Dao archipelago. by Dieter Hug, CC BY 3.0, via Wikimedia Commons
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