Oedolgae

Oedolgae (외돌개) is an intermediate dive site located off the western coast of Jeju Island near the famous Oedolgae Rock, a solitary sea stack that has become one of Jeju's most iconic natural landmarks. Underwater, the site reaches 28 metres and offers a compelling combination of volcanic geology and rich temperate marine life. The Oedolgae sea stack continues its dramatic form beneath the surface, with the volcanic column surrounded by boulder fields and rocky ridges that extend outward from the base. These formations create a complex three-dimensional environment with channels, overhangs, and crevices at multiple depths. The geological interest of the site matches its biological richness, with clearly visible volcanic layering in the rock walls telling the story of Jeju's fiery origins. Soft coral growth at Oedolgae is excellent, with Dendronephthya colonies decorating the walls and overhangs in characteristic Jeju fashion. The site's western exposure means it receives the full force of tidal currents sweeping along the coast, which bring nutrients that fuel the soft coral growth. Sea fans and black coral bushes add additional colour and structural complexity to deeper sections of the reef. The fish community reflects Jeju's position at a marine crossroads. Resident species including various rockfish, wrasses, and blennies are joined by seasonal visitors from warmer waters. Schools of yellowtail and mackerel are commonly sighted, particularly during the summer and autumn months when water temperatures peak. The boulder fields at the base of the site harbour octopuses, lobsters, and moray eels. Current at Oedolgae is the primary factor in its intermediate rating. The water movement around the sea stack can be unpredictable, with eddies and downcurrents forming on the downstream side. Divers should stay alert to changing current patterns and maintain close contact with their buddy and guide. Water temperatures range from 14 to 25 degrees across the seasons, with visibility averaging 10 to 20 metres. The site's proximity to Jungmun makes it accessible from Jeju's main tourism infrastructure.