Udo is reached by ferry, and the practical risk is planning the island like a fixed-timetable attraction. Visit Jeju advises travelers to check the operating status and final departure on the day because sailing hours vary by season, weather and route.
Seongsanpo Port is a main mainland access point in eastern Jeju. Do not arrive with a tight return connection: confirm the day's sailing status before boarding and leave enough buffer to return to Jeju Island.
Vehicle rules matter. Current Visit Jeju guidance says general rental cars are restricted from operating on Udo through July 31, 2029, with limited exceptions including qualifying low-emission rental cars, vehicles used by some mobility-impaired travelers and vehicles used by overnight guests when conditions are met. Confirm eligibility, supporting documents and rental-car insurance before attempting to load a vehicle.
On the island, sightseeing loop buses, bicycles and electric bicycles are among the alternatives. The Udo Marine Provincial Park admission is separate from the ferry fare. The official page currently lists adult park admission at KRW 1,000, but the ferry fare and timetable should be checked separately on the day.
Best practice: verify sailing status and last return; decide in advance whether you are traveling as a foot passenger; if bringing a vehicle, confirm the exception before reaching the terminal; keep weather flexibility in the rest of the day's itinerary.