Jeju Island
South Korea · Korea Strait
Jeju is South Korea's largest island, volcanic, and the country's only meaningful diving destination — kelp forests, lava tubes, basalt walls, and a soft coral ecosystem unusual at this latitude. Cold water and freediving haenyeo (sea women) culture add cultural texture.
How this reef is doing
ⓘ How we measure thisReef state
Subtropical Korean island reef. Coldwater influenced ecosystem; soft coral on the rocks.
Coral cover
Fish life
Heat
No unusual heat right now.
Fishing
Protected on paper, but boats are still busy nearby.
Sources · MERMAID and partner coral surveys · NOAA Coral Reef Watch · Global Fishing Watch and reef gravity
What you will see
12 species across the dive sites here
Lionfish
Seen 7 months ago
at Beomseom (Tiger Island)
Carnation soft coral
Seen 7 months ago
at Munseom
Yellowtail amberjack
Seen May 2025
at Munseom
Least concern
Alveopora coral
Seen Apr 2025
at Munseom
Critically endangered
Giant Pacific Octopus
Seen year round
at Beomseom (Tiger Island)
Least concern
Gorgonian sea whip
Seen year round
at Munseom
Japanese Scorpionfish
Seen year round
at Beomseom (Tiger Island)
Nudibranchs
Seen year round
at Beomseom (Tiger Island)
Scleronephthya soft coral
Seen year round
at Munseom
Tuskfish
Seen year round
at Beomseom (Tiger Island)
Green sea turtle
Seasonal visitor
at Munseom
Least concern
Squid
Seasonal visitor
at Beomseom (Tiger Island)
Dive sites
What divers say
Diving Jeju and watching the haenyeo work the same coastline by lung power was a humbling combination.
Good to know
Water temp
5mm year round; 7mm in winter.