Jellyfish Lake is not near Ngerulmud. Palau's capital is on the big northern island of Babeldaob, as our guide to Ngerulmud explains. The lake is on Mecherchar, one of the Rock Islands in Koror State. Koror State's tourist page puts it 45 minutes by boat from downtown Koror. The lake sits inside the Rock Islands Southern Lagoon, a UNESCO World Heritage site that lies entirely within Koror State and is patrolled by Koror State Rangers. The permits you need are Koror State permits, not national ones.
Are there jellyfish in Jellyfish Lake right now?
The jellyfish are not guaranteed, so check before you go. The Coral Reef Research Foundation (CRRF) has measured the lake's temperature, salinity, oxygen and jellyfish numbers every month since 1999. It posts the results as a simple conditions and forecast page.
| Alert | Meaning |
|---|---|
| Green | Jellyfish present; conditions favour them for the next three months |
| Yellow | Jellyfish present; numbers expected to fall |
| Orange | Jellyfish absent; conditions favour a return within three months |
| Red | Jellyfish absent; no return expected within three months |
The reading from 16 September 2026 was green. The count was in the top band, "+100,000", and unchanged on the previous three months. The water averaged 30.9 °C in the top 12 metres and was cooling. The page also gave the Pacific climate phase as El Niño, which is worth watching: CRRF says a cooling lake tends to mean a good forecast and a warming one a poor forecast.
"+100,000" is the highest band the page reports, not a total. CRRF's lake profile says the lake typically holds about 5 million golden jellyfish, so the band cannot tell you whether today's numbers are near that level.
Why the jellyfish disappear
The golden jellyfish is Mastigias papua etpisoni, a subspecies found only in this lake and named after former President Ngiratkel Etpison. CRRF documented the jellies' disappearance in 1999, after the previous strong El Niño, and again during the extreme 2015/16 El Niño drought, when the last one was seen in May 2016. Their polyps survive on the lake walls. New jellyfish are produced only when conditions are right again; in 2018 the lake began to cool and the population began to increase. By 2019 the population was estimated in the millions again.
The lake also closed for a time, by Palauan custom rather than by statute. Island Times reported in October 2018 that the Rubekul Oreor, Koror's House of Traditional Leaders, placed a bul (a traditional prohibition) on the lake on 1 May 2017 to help the golden jellyfish recover. The bul was lifted on 17 October 2018, after a CRRF study found that the water temperature had returned to normal and the jellyfish were back.
A closed lake is not the only risk. In a November 2022 notice published by the Palau Visitors Authority, the Koror State Governor's office reported that golden jellyfish had fallen to about 56,000 in July, 10% of the April estimate, and to about 34,000 by August. The lake's average temperature had stayed above 31.5 °C, the limit for successful reproduction. The lake stayed open and visitors swam with moon jellyfish instead. You can arrive at an open lake with few golden jellies.
How much is the Jellyfish Lake permit?
The Palau Visitors Authority's Travelers Tips page lists two Koror State permits:
- Rock Islands permit: USD 50, valid for 5 days, for the designated tourist areas of the Rock Islands but not Jellyfish Lake.
- Jellyfish Lake permit: USD 100, valid for 5 days, which also covers the Rock Islands.
Both are sold at the Koror State Ranger office or through authorized tour companies. They are separate from the USD 100 national environmental fee in your airline ticket, which our guide to the Palau Pledge and environmental fee explains.
Koror State's own documents differ on the details. Its fact sheet revised in May 2016 and its visitor permit sheet quote the same USD 50 and USD 100 but say permits are valid for 10 days. They also say permits apply to visitors aged 6 and over. Both sheets date from 2016, so plan on the 5 days now published by the Visitors Authority and ask the ranger or your operator when yours expires.
Rules in the lake
Scuba is banned. The Visitors Authority explains why: the lake is about 30 metres deep, and below roughly 13 to 15 metres a pink layer of bacteria sits over water with no light, no oxygen and toxic hydrogen sulfide. Snorkel at the surface, and don't free-dive down into that layer.
The 2016 Koror State fact sheet also tells visitors to:
- Take nothing into or out of the lake, including rocks, shells and live animals.
- Not handle or touch the jellyfish, which are fragile.
- Avoid putting on sunscreen just before walking up the trail.
The Visitors Authority's visitor guide asks swimmers to stay on designated paths and access points and avoid disturbing wildlife. Access is by boat from Koror, then a short walk on a marked path into the island.
Before you book a Rock Islands tour
Check CRRF's alert colour in the week you book and again a few days before the trip. If it is green, include the lake. If it is yellow, ask your operator what they have seen recently, since the Visitors Authority advises checking conditions close to your travel date. If it is orange or red, CRRF expects no golden jellyfish. In that case a USD 50 Rock Islands permit covers the rest of the lagoon, and you keep USD 50 per person. Confirm whether the permit is already in your tour price before you pay for one separately.