Jellyfish Lake, Eil Malk, Palau

Jellyfish Lake: When Millions Become Thousands

In 2025, golden jellyfish populations in Palau’s Jellyfish Lake dropped to roughly 5,600 individuals – a fraction of the millions that once filled the water. Climate patterns had shifted water temperature and stratification enough to crash the population temporarily. The lake remains open to visitors and moon jellyfish are still present in healthy numbers, but anyone expecting the famous wall-of-gelatinous-gold that fills most photographs should know that what they will find in 2025 and early 2026 looks different. The lake itself – isolated marine water in a limestone bowl surrounded by mangrove and rock – is still one of the more unusual swimming environments on earth. The question is whether you should factor the population fluctuation into your decision to visit.

Jellyfish Lake is a marine lake on Eil Malk Island in Palau’s Rock Islands, a UNESCO World Heritage Site. The lake connects to the ocean through fissures in the limestone but has been isolated long enough that its ecosystem evolved independently. The golden jellyfish (Mastigias papua etpisoni) that normally fill it have lost the stinging capacity of their oceanic relatives because they no longer need it – their prey is the symbiotic algae in their own tissue, which they feed by following sunlight across the lake surface each day. The nematocysts are too small to penetrate human skin. Swimming among them (when they are present in numbers) is the kind of experience that exists nowhere else.

Access and Permits

The Jellyfish Lake permit costs USD 100 per person (ages 6 and up), valid for five days. The Rock Islands permit without Jellyfish Lake access costs USD 50. Most visitors access the lake through day-trip boat operators from Koror, Palau’s main island, on tours that combine the lake with Rock Islands snorkelling. The boat ride to Eil Malk takes 30 to 45 minutes. Standard day tours run USD 100 to 200 per person depending on the operator and what is included.

From the boat dock on Eil Malk, the lake is a 10-minute walk inland along a steep trail. Scuba diving is prohibited – depth changes disturb the hydrogen sulfide layer below 15 metres, which is lethal to jellyfish. Snorkelling only.

In the Water

The lake surface is warm (28 to 30 degrees Celsius). Reef-safe sunscreen is required, not optional; regular sunscreen damages the lake ecosystem. The jellyfish, when present in significant numbers, cluster near the surface and thin out below 5 to 6 metres. The surrounding mangroves and limestone cliffs make the setting distinctive independent of the jellyfish themselves.

The Rock Islands More Broadly

The 445 limestone islands of Palau’s Rock Islands offer some of the world’s best diving in the channels between them. Blue Corner – a reef wall where current concentrates sharks and large pelagic fish – is the benchmark dive. Grey reef sharks, manta rays, and Napoleon wrasse appear in numbers that are unusual anywhere in the Pacific. Divers use reef hooks to hold position against the current and watch the fish come to them.

The argument for visiting Palau even with the jellyfish lake at reduced population is that the Rock Islands diving stands entirely on its own, and a week here without a single jellyfish in the lake would still be one of the better dive trips available anywhere. The Lake is the famous attraction; the reefs are the reason serious divers come back.

Koror Accommodation

Palau has no major international hotel chains. The Palau Pacific Resort is the most established higher-end option (USD 200 to 300 per night). Fish n Fins and DW Motel are mid-range options used primarily by divers. Book well ahead for the October-November and March-April dive seasons.