Kakaban Jellyfish Lake

Kakaban Jellyfish Lake is a brackish marine lake on Kakaban Island, Derawan Archipelago, East Kalimantan, Indonesia — one of only two places in the world where visitors can swim among multiple species of stingless jellyfish.

Overview

Kakaban Island’s interior is almost entirely occupied by a landlocked marine lake of approximately 5 hectares. Estimated to be over 11,000 years old, the lake formed when tectonic uplift sealed a lagoon from the open sea, creating a brackish environment of seawater mixed with rainwater. The isolation allowed four jellyfish species to evolve over millennia in the absence of significant predators — their stinging cells have weakened to the point of being harmless to humans. Scuba Junkie Sangalaki describes the experience as feeling “like you’re in a sci-fi movie,” surrounded by thousands of pulsing jellyfish in jungle-rimmed silence. Note: scuba diving is not permitted inside the lake — only snorkelling is allowed, to protect the fragile ecosystem.

Marine Life

Four endemic jellyfish species inhabit the lake:

• Spotted jellyfish (Mastigias papua) — the most abundant; grows to 20 cm across; visible immediately upon water entry
• Moon jellyfish (Aurelia aurita) — largest species, up to 30 cm across; transparent and plate-shaped
• Upside-down jellyfish (Cassiopea ornata) — found on the lake bed; approximately 20 cm diameter
• Box jellyfish (Tripedalia cystophora) — smallest species, body under 1 cm with 3–4 cm tentacles; difficult to spot due to transparency

Other lake inhabitants: blue flatworms, file snakes, cardinalfish, and sea cucumbers.

Dive Profile

The lake reaches 17 metres at its deepest point, but snorkelling is the permitted activity — no scuba equipment is allowed inside. Snorkellers float on the surface among the jellyfish, which are distributed throughout the water column. Visibility is generally good in the upper water layers. Visitors typically spend 45 minutes at the lake during a surface interval between open-water dives.

Entry and Exit

Shore entry from a small wooden platform at the lake edge. Reaching the lake requires a 5-minute walk up wooden steps and across a bridge through forest from the island’s jetty. Access is typically packaged as a surface interval stop between dives at Barracuda Point or other Kakaban sites.

Tips

• Fins are prohibited inside the lake — kicks stir up the sandy bottom and reduce visibility dramatically.
• Non-reef-safe sunscreen must not be worn — the chemicals are toxic to the jellyfish and the enclosed ecosystem.
• Do not jump into the lake; step in gently from the wooden platform.
• Do not touch or attempt to hold jellyfish.
• Duck diving (skin diving) is not permitted.
• Bring a rash guard or thin wetsuit — the water is warm but a full hour in water warrants sun protection.
• An entry donation of approximately 20,000 Rupiah is requested.

Safety Considerations

The jellyfish stings are negligible, but some individuals may experience minor skin sensitivity. The walk to the lake involves steps and uneven terrain in tropical heat — wear footwear with grip. Hydration before the walk is advised.

Photography

The jellyfish lake offers extraordinary opportunities for wide-angle snorkel photography — shooting upward with jellyfish backlit by filtered jungle light is the signature image. The spotted jellyfish’s brown and white patterning contrasts well against the blue-green water. A compact camera in a housing or action camera works well from the surface.

Site Information

• Location: Kakaban Island, Derawan Archipelago, East Kalimantan, Indonesia
• Entry Type: Shore entry
• Site Type: Beach dive
• Difficulty Level: Beginner
• Maximum Depth: 17 meters

Additional Resources

• Last Updated: 2026-05-17

Sources: Scuba Junkie Sangalaki – Kakaban Stingless Jellyfish Lake, Asia Dive Site – Kakaban, Dive The World – Sangalaki, Asia Diving Vacation – Kakaban Island. Last updated 2026-06-27.