Derawan Islands

For the most consistent sea conditions, many travelers target the drier stretch from April to October, when crossings are smoother and visibility is often better. Water temperature stays warm around 28°C year-round, so season is more about wind, rain, and surface chop than cold water. Diving can be good in any month, but snorkelers and freedivers usually prefer May to September for calmer surfaces. If you travel in November to March, build in flexibility for weather delays and plan sheltered-site backups.

Most routes start with a flight to East Kalimantan, then continue through Berau. A common pattern is Jakarta or Bali to Balikpapan (BPN), then a domestic connection to Berau's Kalimarau Airport (BEJ). From BEJ, transfers usually go by car to Tanjung Batu jetty, followed by a speedboat to Derawan or your chosen island base. Because boat departures can be weather-dependent, arrive early in the day and avoid tight same-day flight connections on the way out.

There is not always a single, standardized marine park tag. Instead, visitors often encounter local retribution tickets and site-specific fees for community-managed attractions such as lagoons, caves, or Kakaban lake access. Dive operators may bundle these fees into packages, but not always, so ask what is included and bring IDR cash for on-site payments. Regardless of fees, treat all sites as conservation areas: do not touch wildlife, control buoyancy, and follow any local rules that protect sensitive habitats.

Choose Derawan if you want simpler logistics, village atmosphere, and easy snorkeling or warm-up dives right off jetties and nearby reefs. Choose Maratua if your priority is wall diving, current-driven sites, and a more resort-style base spread across a larger atoll. Many visitors split the trip: a few nights on Maratua for action days, then a few on Derawan for relaxed reefs and easier transfer timing. If mantas are your top goal, make sure your plan includes dedicated day trips to Sangalaki.

Sangalaki is the manta headline, with well-known sites such as Manta Point Sangalaki and Cleaning Station Sangalaki. These are typically shallow sand or reef-edge zones where mantas may pass through to feed or be cleaned. Manta presence is influenced by tide and visibility more than month, so schedule multiple manta-focused trips rather than betting everything on one day. Keep your approach low-impact: stay still, avoid blocking the manta's path, and never chase or touch.

Currents range from gentle on sheltered reefs to very strong on points and wall corners, especially around Maratua and some Kakaban and Sangalaki sites. Open Water divers can enjoy many dives, but Advanced-level comfort is helpful for drift dives, negative entries, and deeper wall profiles. The most important factor is experience with current procedures and buoyancy control. Carry an SMB, stay close to your guide, and be willing to switch to a sheltered site if conditions are beyond your comfort level.

Go early, follow the local briefing, and keep your impact close to zero. Rules can vary, but many visitors are asked to avoid fins and avoid sunscreen in the lake to protect the ecosystem. Wear a rashguard instead of relying on lotion, move slowly, and never touch or lift the jellyfish. Keep noise down and do not bring food into the water. Because the lake is brackish and sheltered, it can feel warm and still. Rinse after and monitor for irritation if you have sensitive skin.

Operator materials for the Derawan region commonly cite Balikpapan as the nearest established recompression chamber location, and reaching it from the islands can take many hours depending on sea state and flight availability. Some resort documents also mention a newer chamber in the Tanjung Batu area that may be available, but you should not plan your safety around it without confirmation. The practical approach is to dive conservatively, keep strong surface intervals, and carry dive insurance that covers evacuation and chamber treatment.

Plan to be cash-forward. Resorts may accept cards, but many practical expenses such as local entrance fees, small shops, and occasional boat add-ons are cash-only. ATMs are most reliable in Tanjung Redeb (Berau) and around major hubs, and you should not assume there will be a working ATM on your island. Withdraw before leaving town, keep small bills, and carry a buffer for weather delays that might add an extra night or change transfer plans.