Jeju

Jeju is a shield volcano with a ring road around it. Hallasan, the peak in the middle, is the highest mountain in South Korea and the summit trails are long day walks with fixed cut-off times and a reservation system. Around the edge sit the things most people come for: Seongsan Ilchulbong, the tuff cone rising straight out of the sea on the east coast; the Manjanggul lava tube; the black cliffs and turquoise water of Udo, a short ferry off the eastern tip; and a coastal road with a different view every twenty minutes.

The island is bigger than it photographs. Driving the ring road is around two hundred kilometres, and the east and west coasts are genuinely separate days. Buses exist and are cheap, but they are slow and radial, which means most cross-island journeys route back through Jeju City. A rental car is close to mandatory, and it is the thing to book first — supply tightens on weekends and around national holidays, and the desks are off-airport with a shuttle and a queue.

Bring the paperwork. Rental firms expect your home licence, your passport and a valid International Driving Permit, and the IDP has to be arranged in your own country before you leave. Turning up with a licence alone ends the trip at the counter.

Getting here is a flight or a ferry, not a train. Flights from Seoul are about an hour and from Busan under an hour, and the Seoul–Jeju route is one of the busiest in the world, so fares are usually low but the seats around holidays are not. Typhoon season runs through late summer and cancellations do happen, which is another argument for putting Jeju at the end of a route with a spare day rather than in the middle of one.