Palau · Micronesia

Rock Islands

Dry-season conditions usually make inter-island boat travel easier.

The Rock Islands in Palau's southern lagoon include the famous Jellyfish Lake — a saltwater pond cut off from the sea where golden jellyfish have evolved with reduced stings, allowing snorkelers to swim among millions of them. Plus countless dive sites among the limestone islands.

Good season

Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Year-round; November–May is drier. Jellyfish population fluctuates with ENSO cycles.

Trip duration

5–7 nights as part of a Palau trip.

Dive style

Snorkel-only for Jellyfish Lake; scuba on surrounding island walls and channels.

Dive level

All levels for jellyfish snorkel; Advanced for Rock Island dives.

Reef health

What you’ll actually find
Holding steady

One of the few reefs whose live coral has held up over the last decade. Plan with confidence.

Coral reef health

How is this calculated?
A decade ago
Survey 2014
40%
Today
Survey 2024
40%

Heat stress right now

Watch

Mild warmth. Worth watching — no bleaching yet.

NOAA Coral Reef Watch · updated May 2026 · 1 °C-week heat dose

What to expect on a dive

Rock Islands marine lakes and outer reefs both remain in strong condition under Palau's national MPA regime.

Sources, methodology, and the raw numbers

Raw observed numbers

  • Coral cover: 40% (survey Sep 2024, Local Pacific reef survey)
  • Bleached: 6%
  • Recent mortality: 2%
  • Pacific refugium — observed condition reflects the stable regional pattern.

Raw thermal numbers

  • NOAA CRW alert level: Watch
  • Degree Heating Weeks: 1 °C-wk
  • SST anomaly: +0.4 °C

How we summarise this

Observed coral cover, bleaching, and mortality come from named in-situ surveys with a stated date and method — they describe one snapshot of one reef and do not extrapolate to neighbouring sites. Current thermal stress is satellite-derived from NOAA Coral Reef Watch at ~5 km resolution; it indicates risk, not observed coral damage. We deliberately separate observed condition, current thermal stress, and projection — and we never publish a projection without a documented model and uncertainty.

Sources

Reef condition changes year to year. If you visit, consider supporting responsible-travel and conservation operators on the ground.

Pressure on this reef

Protection · fishing · what you can do

Protected-area status

No-take reserve

Fully no-take — no fishing of any kind. The strongest protection tier.

Fishing pressure

Low fishing pressure

Dominant pressures

  • dive tourism
  • warming

3 Green Fins-verified operators known at this location.

What you can do

Palau National Marine Sanctuary protects 80% of the EEZ as no-take. The Palau Pristine Paradise Pledge is signed on arrival — read it and live it.

Protection status sourced from Protected Planet / WDPA and refined with Marine Protection Atlas. Fishing pressure proxy is Global Fishing Watch AIS data. See the methodology for what these sources can and can’t prove.

Dive sites here

2 curated

Gear

What to bring

Basic kit

Site-specific add-ons

Some dive sites here call for extra gear. Check the individual site page for full context.

  • Reef hookHook-in at the channel entrance is the standard technique to watch sharks and snappers without finning against the current. · Ulong Channel
  • Surface marker buoyDrift exits the channel into open water — operators require SMB for pickup. · Ulong Channel

What divers say

Floating in a million pulsing golden jellies in a lake on top of an island — Palau's strangest hour underwater.
Guest