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Hotels, dive operators, gear, and how to get here are on the Rock Islands location page.
Overview
A marine lake on Eil Malk island in the southern Rock Islands, cut off from the sea since the last ice age and reached by a short climb over a limestone ridge from the boat landing. Snorkelers cross water thick with golden jellyfish (Mastigias papua etpisoni), an endemic subspecies that lost most of its sting in isolation and pulses across the lake each day to keep its symbiotic algae in sunlight. Moon jellyfish drift through the same surface layer. Scuba is banned: exhaled bubbles lodge under the bells and harm the animals, and a hydrogen sulfide layer below 15 m is dangerous to breathe near. Golden jellyfish numbers swing with climate, from tens of millions in good years to near total collapse and back.
Briefing note
Permits: requires the Rock Islands / Koror State permit plus a separate Jellyfish Lake permit, usually bundled by operators with the Palau Pristine Paradise Environmental Fee paid on arrival. Snorkel only, no scuba. Rinse off sunscreen and oils before entering to protect the lake. Golden jellyfish densities have crashed and recovered repeatedly with El Niño warming, so the spectacle varies widely by year; confirm current status before booking.
What you'll see
3 species curated- year-roundGolden jellyfish
- year-roundMoon jellyfish
- year-roundJellyfish-eating anemone
Conditions
| Month | Water | Visibility | Current |
|---|---|---|---|
| Jan | 28–30 °C | 6–12 m | none |
| Feb | 28–30 °C | 6–12 m | none |
| Mar | 29–31 °C | 6–12 m | none |
| Apr | 30–32 °C | 6–12 m | none |
| May | 30–32 °C | 5–10 m | none |
| Jun | 30–32 °C | 5–10 m | none |
| Jul | 30–32 °C | 5–10 m | none |
| Aug | 30–32 °C | 5–10 m | none |
| Sep | 30–31 °C | 5–10 m | none |
| Oct | 29–31 °C | 5–10 m | none |
| Nov | 29–30 °C | 6–12 m | none |
| Dec | 28–30 °C | 6–12 m | none |
Season calendar
Peak season highlighted · current month outlined
Gear for this site
Beyond the basic kit- Snorkel and mask (no scuba) — Scuba is prohibited in the lake; the visit is a surface snorkel, so mask, snorkel and fins are all you take in.
- Rash guard — A thin layer guards skin against incidental contact with the mild jellyfish and against sun on the long surface swim.
Next step
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