Dodong is Ulleungdo's main harbour town on the east coast, and the boat diving worked out of it: volcanic rock and kelp to a maximum of about 30 m, with the cold-water species of the East Sea rather than anything tropical. Visibility runs 20 to 40 m and regularly past 30 m in the peak weeks from late July to mid-September, when the water reaches 20 to 24°C.
Also known as Dodong Harbor.
Where it is and how deep
37.4809° N, 130.9093° EApproximate position — the dashed circle shows where the site lies; your operator's briefing has the mooring.
The dive
The diving here is boat work off the harbour on the volcanic rock that makes up the island's coast, and the profile is straightforward: rock and slope to a maximum of about 30 m, with no hard coral and very little sand. The life is the cold-water cast — rockfish, scorpionfish, sea bream and filefish on the structure, octopus and squid working the ledges, abalone and sea urchin on the shallower rock, and kelp where the light reaches. Dolphins are among the species recorded here.
Conditions are moderate current and 20 to 40 m of visibility, regularly past 30 m in the peak stretch from late July to mid-September when the water sits at 20 to 24°C. The season runs June through October; outside it the water is a good deal colder, and exposure protection should be picked for the bottom of the range rather than the top. The bigger planning risk is not the dive but the crossing: ferries take two and a half to three hours and are cancelled outright in rough weather, particularly in winter and early spring.
Marine life and season
- Squid
- Octopus & cuttlefish
- Dolphins
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Off-season | Off-season | Fair | Good | Good | Good | Prime | Prime | Prime | Prime | Good | Off-season |
Season follows Ulleungdo: Jul–Oct is warmest and clearest; winter storms in the East Sea stop the ferry for days and close the season entirely.
Know before you go
- Water outside the late-July to mid-September peak is well below the 20–24°C reading, so pick exposure protection for the cold end of the range.
- Ferries from the mainland cancel in rough weather, particularly in winter and early spring — build spare days at both ends rather than a tight dive schedule.
Questions divers ask
How deep is the diving at Dodong?+
About 30 m at the deepest. The rock slopes down from the shallows and the dive is normally run well inside recreational limits, which is why it tends to be the first dive of a trip rather than the deep one.
When is the best time to dive Dodong?+
Late July through mid-September. That is when the water is 20 to 24°C and visibility regularly exceeds 30 m against a 20 to 40 m range. The wider season runs June to October; outside it the water is considerably colder and the mainland ferries are less reliable.
Sources
- Ulleungdo Island — Diving in Dodong, South Korea — DiveOne Club
- OpenStreetMap — 도동항 — OpenStreetMap
Photo credits
- Aerial view of Dodong harbor, a curved bay of houses and boats framed by steep forested cliffs on Ulleungdo by Raki_Man, CC BY 3.0, via Wikimedia Commons
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