Kakaban

Kakaban is a raised coral atoll that was uplifted 40 to 60 metres above sea level during the Holocene epoch. The former lagoon lost all surface connections to the sea. It maintains a marine character entirely through an unmapped network of microscopic fissures in the porous limestone bedrock. This restricted hydrological exchange creates a dampened tidal environment where the water is brackish and heavily stained green by tannins from the surrounding mangroves. The isolation created an environment with virtually zero dispersal potential. The marine animals trapped inside evolved rapidly and diverged from their oceanic ancestors.

The most famous residents are 4 species of jellyfish that adapted to a predator-free environment. The golden jellyfish is the most prominent. It lost its white spots and its stinging capability entirely. The moon jellyfish drifts in the mid-water and relies on passive ciliary filter-feeding in the current-free water. The upside-down jellyfish spends its life resting on the lakebed to maximise sunlight exposure for its internal algae. A miniature box jellyfish hunts near the mangrove perimeters. The golden and upside-down jellyfish function as complex holobionts. They host vast quantities of photosynthetic algae within their tissues. The golden jellyfish perform a daily horizontal migration across the lake to follow the sun and optimise this symbiotic relationship.

Because the anchialine lake possesses a severely limited water exchange rate it is highly sensitive to external inputs. Chemical pollution from synthetic UV filters in sunscreens accumulated in the water column and acted as endocrine disruptors. This pollution combined with a strong El Nino warming event damaged the photosynthetic machinery of the algae. The jellyfish starved and the visible population vanished by December 2023.

The East Kalimantan Natural Resources Conservation Agency (BKSDA) and local authorities led a scientific investigation into the collapse. They closed the island completely to allow the ecosystem to recover. Kakaban officially reopened on 16 February 2025 under a strict conservation-first regulatory framework. Swimming in the lake is now strictly banned. You must observe the jellyfish exclusively from a new two-kilometre wooden boardwalk and elevated observation decks. Visitor numbers are capped at a daily cap of about 100 visitors. You must be accompanied by a mandatory certified local guide at all times. Sunscreen, body lotions and insect repellents are strictly prohibited on the island and all in-water gear is banned from the lake vicinity.

The outer perimeter of Kakaban offers sheer drop-offs and intense currents.

Barracuda Point

Skill level: Advanced (Reef hook strictly required) | Ave depth: 15 m | Max depth: 25 m This steep coral wall acts as a natural funnel for tidal waters and creates fierce sweeping currents. Swimming against the flow is impossible so the use of a reef hook is strictly required. You secure your hook to non-living rock and hang suspended in the water column. The site is named for the schools of chevron barracuda (Sphyraena qenie) that often form tornadoes in the current. You often see bigeye trevally (Caranx sexfasciatus), rainbow runners and patrolling grey reef sharks (Carcharhinus amblyrhynchos).

Blue Light Cave

Skill level: Advanced / Cavern Certified | Ave depth: 21 m | Max depth: 44 m This is an advanced overhead environment that penetrates deep into the island's limestone foundation. You enter through a narrow hole on the shallow reef flat and descend a vertical chimney into a massive subterranean cavern. The primary exit is a vertical fissure in the outer drop-off wall at 44 m. Sunlight filtering through this crack gives the cave its name. This dive requires specialised cavern certification and rigid adherence to overhead safety protocols. The sheer vertical nature of the drop-offs requires immense depth discipline. A diver perished near the Kelapa Dua wall in 2025 after descending past recreational limits to retrieve a camera.

Cabbage Coral

Skill level: Open Water / Intermediate | Ave depth: 15 m | Max depth: 25 m This gently sloping reef offers a calm alternative to the high-energy drift sites. It features massive overlapping colonies of cabbage coral bathed in ambient light. The reef provides shelter for dense aggregations of anthias and resting sea turtles.

The Wall

Skill level: Advanced | Ave depth: 20 m | Max depth: 30 m The limestone face here drops vertically down to depths exceeding 250 m. You drift along the upper section and inspect the cavernous indentations for moray eels. Look out into the blue water for passing pelagic fish.

The interior lake provides an up-close look at evolutionary adaptation. From the viewing platforms you can look for golden jellyfish pulsing through the green water and upside-down jellyfish resting on the lakebed. The outer reefs offer a complete contrast. You often find intense pelagic action along the sheer drop-offs. Dense schools of chevron barracuda and bigeye trevally gather in the currents. Grey reef sharks and whitetip reef sharks (Triaenodon obesus) often patrol the walls. With luck you might spot scalloped hammerhead sharks (Sphyrna lewini) out in the deep blue.

You can dive Kakaban all year. The best visibility runs from March to October. The marine lake is highly susceptible to climate anomalies and prolonged El Nino events can raise the water temperature and stress the recovering jellyfish population.

The journey from Sabah to the Derawan Archipelago involves multiple modes of transport and takes 36 to 48 hours. The direct geographic path crosses the maritime border between Tawau in Malaysia and Tarakan in North Kalimantan; flying takes you via Kuala Lumpur and Balikpapan with a domestic connection to Berau followed by road and boat transfers.

The first leg involves a taxi transfer from Semporna to Tawau City after your final day of diving. Island boats do not run after dark so you spend the night in Tawau. You take an international ferry across the border the next morning. You can take a direct ferry to Tarakan or cross to Nunukan first and connect to a domestic speedboat. Direct ferries from Tawau to Tarakan do not operate on Sundays so your departure day must be planned carefully. Both routes bring you to Tarakan by the mid-afternoon for a second overnight stay.

The final leg is a private charter speedboat from Tarakan to the islands. This open-water crossing takes about 3 hours depending on sea conditions. If severe weather prevents the sea crossing the team arranges a longer overland detour via Tanjung Selor and Tanjung Batu.

You must clear customs and immigration at the port boundaries. The entry and visa requirements vary by nationality and crossing point. Many visitors apply for an electronic Visa on Arrival ahead of time to prevent delays at the port. The team briefs every diver on the exact paperwork needed at booking. The details are confirmed at enquiry.

Nobody stays on Kakaban Island itself. You base yourself at a dive resort on Derawan or Maratua and visit Kakaban as a day trip. The resorts offer wooden water chalets and beach rooms with easy access to the surrounding muck diving and manta ray sites.

This destination suits experienced expedition-minded divers who put first unique marine biodiversity over practical convenience. The Semporna islands are a better fit if you want an easy transfer or if you are travelling with young children. The multi-day transit between Sabah and Kalimantan is physically demanding and involves rugged border crossings. The facilities in the Derawan Archipelago operates largely off the financial grid so you must carry enough Indonesian currency to cover your expenses.

Pairing Sipadan with the Derawan Archipelago creates a diverse Borneo dive circuit. You dive the steep drop-offs of Sipadan and the shallow reefs of Kapalai before crossing the border to explore Sangalaki and Kakaban. Sipadan is completely closed to all visitors every November so this combination must be planned for the open months. Allow 2 days for travel between the two regions. You must plan for the travel time and embrace the journey as part of the expedition.

• Derawan
• Maratua
• Sangalaki
• Sabah and Kalimantan
• Getting there

Send your dates, the names of everyone coming and your certification levels. The team comes back with the options and availability that fit your trip.