Jeollanam-do dive sites

Geomun Island is reached by ferry from Yeosu, with departures taking approximately one and a half to two hours. Yeosu is connected to Seoul by KTX high-speed rail in about two and a half hours, and has a domestic airport with flights from Seoul Gimpo. The island has limited accommodation, mostly guesthouses and minbak, and dive operators are small-scale, often requiring advance booking. Some Yeosu-based dive shops arrange day trips to the outer islands, but staying on Geomun Island itself provides better access to the best dive sites on the outer reefs.

Geomun Island sits at the ecological boundary where the warm Tsushima Current from the south meets cooler Korean coastal waters, creating a transition zone with unusual species overlap. Temperate species like kelp forests, rockfish, and abalone share the reef with subtropical visitors including tropical nudibranchs, soft corals, and occasional tropical fish that arrive with warm current pulses during summer. This biogeographic crossroads supports higher species diversity than either purely temperate or subtropical Korean waters. Researchers have documented over 300 marine species in the surrounding waters.

Water temperature at Geomun Island varies dramatically by season, from around 12 degrees Celsius in winter to 25 degrees in late summer. During the prime diving season of June through October, a five-millimetre wetsuit is suitable for most divers in July and August, but a seven-millimetre suit or semi-dry is recommended for June, September, and October. A hood is advisable even in summer, as thermoclines can produce sudden temperature drops of five degrees or more at depth. Dry suits are standard for the few operators running winter dives.