Derawan Islands

The Derawan Islands are one of Indonesia’s most varied and underrated liveaboard destinations — four islands, each with a completely different diving identity, packed into a compact 31-island archipelago off the east coast of Borneo. Sangalaki delivers year-round manta ray encounters and Indonesia’s largest green turtle nesting population. Kakaban holds one of the world’s only stingless jellyfish lakes plus a world-class outer reef wall at Barracuda Point. Maratua produces some of the strongest drift dives in Indonesia, with chevron barracuda tornadoes, eagle rays, and occasional thresher sharks. Derawan Island itself is a dedicated macro paradise with blue-ringed octopus, multiple ghost pipefish species, harlequin shrimp, and mandarin fish at dusk. Coral diversity here ranks second only to Raja Ampat across Indonesia — with a fraction of the visitor numbers.

The best season runs from March to October, with peak conditions from July to September. This dry season window brings the clearest visibility, calmest seas, and the most active whale shark gatherings at the offshore bagans. July to September is also when manta ray activity peaks at Sangalaki’s cleaning stations, coinciding with plankton blooms that draw multiple animals simultaneously. Green turtle nesting runs year-round on Sangalaki’s beaches, with hatchlings emerging primarily from June to October. November to February is the off-season — rougher seas, reduced visibility from plankton blooms, but the inner reef sites remain diveable and the destination sees even fewer visitors.

Derawan liveaboards embark from Tanjung Batu, a small coastal town near Berau in East Kalimantan. The nearest airport is Kalimarau Airport (BEJ) in Berau, connected to Jakarta (CGK) and Balikpapan (BPN) by Garuda Indonesia and Lion Air. From Bali or Singapore, the most common routing is via Balikpapan — a major Kalimantan hub with good connections. From Berau airport, a 2-hour road transfer reaches Tanjung Batu, where your liveaboard awaits. Plan a full buffer day for the domestic connections — weather delays into eastern Borneo are common and missing the boat departure is a real risk. Confirm pickup arrangements with your operator in advance.

The Derawan Islands cater to a wide range of experience levels. Sangalaki’s manta cleaning stations, Turtle Bay, and Derawan Island’s macro sites are all calm, low-current dives accessible to Open Water certified divers. The jellyfish lake on Kakaban is snorkel-only and requires no dive certification at all. Maratua’s channel dives — Big Fish Country and The Channel — involve powerful tidal currents and require Advanced Open Water certification and drift diving experience. Barracuda Point on Kakaban’s outer reef can also have significant current. Liveaboard dive guides assess conditions at each site and will match groups to appropriate sites based on certification and comfort level.

Kakaban’s jellyfish lake is one of only a handful of such lakes in the world. Thousands of years ago, rising land trapped seawater — and the jellyfish living in it — inside a limestone basin on the uninhabited island. Cut off from ocean predators, the jellyfish gradually lost their stinging cells over generations of evolution, as stinging provided no survival advantage. Today the lake holds millions of golden mastigias jellyfish and moon jellyfish that are completely harmless to touch. A short jungle walk from the boat landing leads through limestone forest and mangroves to the lake edge. The visit is snorkel-only — scuba is not permitted to protect the lake’s fragile ecosystem. Do not use sunscreen before entering, as the chemicals harm the jellyfish. The experience is unlike anything else in dive travel.

Sangalaki is one of the most consistent year-round manta ray destinations in Indonesia. The island’s inner reef cleaning stations attract reef mantas almost daily — single individuals, courting pairs, and during plankton blooms, training groups of five or more animals circling the same station simultaneously. Visibility at the cleaning stations typically runs 15–25 metres, and the calm, low-current conditions make it accessible to all dive levels. Unlike some manta destinations where encounters are tide-dependent, Sangalaki’s mantas visit throughout the dive rather than in short windows. July to September sees the highest activity as plankton blooms peak. Most divers on a Derawan liveaboard see mantas on multiple separate dives during their trip.

Sangalaki hosts the largest green turtle nesting population in Indonesia — over 15,000 female green turtles return to its beaches annually to lay eggs, making it one of the most significant sea turtle nesting sites in Southeast Asia. A local hatchery program on the island collects and protects eggs from the most vulnerable nests, incubating them safely and releasing hatchlings into the sea. In the water, green turtles are present on virtually every dive around Sangalaki — resting under coral bommies, grazing seagrass at Turtle Bay, and surfacing for air throughout the dive. Hawksbill turtles are equally common elsewhere in the archipelago. The population density of turtles in Derawan is among the highest of any Indonesian dive destination.

Maratua Atoll’s channels produce some of the most exhilarating drift dives in Indonesia. Powerful tidal exchanges funnel through the narrow gaps between the atoll walls, creating racing currents that concentrate marine life — chevron barracuda in spiraling tornado formations, schools of eagle rays, grey reef sharks, large tuna, and occasional thresher and hammerhead sightings. Big Fish Country is the signature site: divers hook in with reef hooks to hold position against the current and watch the parade of pelagics pass by, then unhook and let the current carry them along the wall. The Channel involves even stronger flow that shifts direction with the tide. Both sites require Advanced Open Water certification, solid buoyancy control, and comfort with drift diving — they are not appropriate for Open Water divers or anyone without current experience.

Yes — whale sharks gather year-round at offshore fishing platforms (bagans) near Berau and Maratua, drawn by bycatch from the nets in the same way as Cenderawasih Bay. The Derawan whale shark experience is less developed and publicised than Cenderawasih’s but increasingly reliable, with peak activity from July to September. Individual whale sharks up to 12 metres have been documented at the platforms. The encounter is less structured than at Cenderawasih — operators locate active bagans each day rather than visiting a fixed platform — but when conditions align, the experience is equally extraordinary. Most Derawan liveaboard itineraries include at least one bagan visit during the peak season.

The Derawan Islands are well suited to non-divers and mixed groups. The jellyfish lake on Kakaban is one of the world’s great snorkeling experiences and requires no dive training. Manta ray encounters at Sangalaki’s cleaning stations are accessible from the surface. Green turtle watching on Sangalaki’s nesting beaches at dusk or dawn is a compelling topside activity. Maratua’s inner lagoon — shallow, brilliantly turquoise, ringed by jungle — is ideal for kayaking and paddleboarding. Visits to Bajau sea gypsy stilt villages on Maratua, the Sangalaki turtle hatchery, and the jungle walk to Kakaban’s lake are all non-diving activities that stand on their own merits.

Most Derawan Islands liveaboards run 7–10 nights, which is sufficient to cover all four main dive islands comfortably — Sangalaki, Kakaban, Maratua, and Derawan — with multiple dives at each. A 7-night trip is the minimum to do the archipelago justice; 10 nights allows for unhurried diving, repeat visits to the best sites at optimal tide conditions for Maratua’s channels, and time for topside activities including the turtle hatchery and jellyfish lake. Unlike most other Indonesian liveaboard destinations, Derawan rarely combines with adjacent regions on crossing itineraries due to its geographic isolation off Borneo’s east coast — most trips are standalone Derawan-only itineraries.

Water temperature in the Derawan Islands ranges from 27–29°C year-round, with occasional cooler upwellings reaching 23°C in Maratua’s channels during strong tidal flow. A 3mm wetsuit is comfortable for most divers at the calmer sites. A 5mm is worth bringing for the deeper channel dives at Maratua and for extended bottom times on Derawan Island’s macro sites. Visibility ranges from 15–25 metres typically, reaching 30m in the dry season at the outer reef sites. During plankton blooms in July to September, visibility can drop to 10–15m at the cleaning stations — a tradeoff worth accepting, as the blooms are exactly what brings the mantas and whale sharks in peak numbers.