Advice for diving Jelly Fish Lake in Palau

Jellyfish Lake is a marine lake on one of Palau’s Rock Islands about an hour boat ride from Koror. Once on the island there is a short 10 minute uphill and then downhill hike required to get to the lake. Often muddy from rain the trail can be a bit slippery and there is a rope rail most of the trail to hold on to. Shoes are definitely recommended as sandals are likely to get stuck in the thick mud.

The jellyfish move from one side of the lake to the other throughout the day following the sun movement. During the morning the jellyfish will be closer to the dock and later in the day they will be on the other side of the lake, a further swim from the dock. The lake isn’t very large, so the longest swim is probably 15-20 minutes later in the day.

The jellyfish in Jellyfish Lake have lost their ability to sting so divers can touch them and most people have no reaction. Some people who have severe allergies to jellyfish or other stings may still feel a sting or have a reaction. Often people can feel a small sting around their mouths and lips if a jellyfish brushes the face.

Scuba is not allowed in Jellyfish Lake because diver’s exhaled air bubbles can be trapped in the bell of the jellyfish, killing them. The jellyfish are also quite delicate and a strong fin kick can break them into many pieces. The lake has hydrogen sulfide at the bottom which can poison divers though the skin. (Being on the surface is fine as the hydrogen sulfide is deeper.) Free diving is discouraged because of the hydrogen sulfide in deeper waters and because strong fin kicks can damage the jellies.

Be sure to also look for the lake’s other residents. There is an anemone (most easily seen near the dock and around the tree roots at the edges of the lake) that are the only predator of the jellyfish. A species of moon jellyfish is also in the lake, although their numbers have decreased in past years, and cardinal fish can also been seen near the dock and at the lake’s edges.

The lake has great conditions year round although if there has been a lot of heavy rain the rain water sometimes pushes the jellies deeper than normal. (Usually they come all the way to the surface).

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