When To Go · Destination Guide
Derawan Islands
Mantas, turtles, and a stingless jellyfish lake in a remote Coral Triangle corner of Borneo
Updated Dec 13, 2025 • 12 sources
When To Go
Season planner for Derawan Islands
Derawan is equatorial and warm year-round, with water often around 28°C. A common planning split is a drier window (often April - October) with more consistent seas and visibility, and a wetter window (often November - March) with more rain and occasional chop. Diving can be good in any month, but snorkelers and freedivers generally prefer the calmer, drier stretch.
At A Glance Heatmap
| Activity | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
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| Freedive | ||||||||||||
| Snorkel | ||||||||||||
| Topside |
Activity Drilldowns
OverallApril - October·Crowd:Moderate·Cost:Moderate
Ideal: Drier weather, steadier seas, and more consistent visibility. Water stays around 28°C.
Plan Carefully: Wetter monsoon months can bring heavier rain and choppier crossings, especially when winds build to 20.0 kph or more.
Holidays can shift prices: Indonesian school holidays and major festivals (often June August) can raise demand.
ScubaApril - November·Crowd:Moderate·Cost:Moderate
Ideal: More days suitable for point and wall dives, with visibility often closer to 20 m or better.
Plan Carefully: Often diveable, but prioritize sheltered reefs if crossings are rough and expect more rescheduling.
For currentfocused sites, timing beats season.
FreediveMay - September·Crowd:Low·Cost:Value
Ideal: Calmer surface conditions make line sessions and deep training safer and more enjoyable.
Plan Carefully: More surface chop and rain can reduce visibility. Focus on technique days in protected water.
Freediving is most enjoyable when the surface is calm.
SnorkelMay - September·Crowd:High·Cost:Moderate
Ideal: Better visibility and calmer seas on reef flats, especially for manta-focused day trips.
Plan Carefully: More rain and chop can reduce comfort. Plan lagoon and village days as backups.
Snorkel success is about surface conditions.
TopsideApril - October·Crowd:Moderate·Cost:Value
Ideal: More reliable boat crossings and clearer skies for viewpoints and sandbar photos.
Plan Carefully: Heavier rain can make trails slick and reduce visibility at viewpoints. Keep cave or village activities as flexible options.
Caves and lagoons can be visited yearround, but sandbars and long crossings are more weatherdependent.
Seasonal Callouts Timeline
Manta rays around Sangalaki
JanJanFebFebMarMarAprAprMayMayJunJunJulJulAugAugSepSepOctOctNovNovDecDecMantas are a headline feature of Sangalaki. Conditions and tide matter more than month, so plan multiple attempts if mantas are a priority.
Green turtle nesting and hatchlings
JanJanFebFebMarMarAprAprMayMayJunJunJulJulAugAugSepSepOctOctNovNovDecDecTurtles are common year-round, but nesting activity often peaks in the middle of the year on key beaches. Follow local guidance and avoid lights on nesting beaches.
Kakaban lake swim conditions
JanJanFebFebMarMarAprAprMayMayJunJunJulJulAugAugSepSepOctOctNovNovDecDecDrier months usually mean easier logistics and more comfortable lake swims. Follow local rules (commonly no fins and no sunscreen).
Whale shark chances on Berau coast (bagan platforms)
JanJanFebFebMarMarAprAprMayMayJunJunJulJulAugAugSepSepOctOctNovNovDecDecSome itineraries add a mainland coast day for possible whale shark encounters around fishing platforms. Sightings are not guaranteed.