Jeju or Okinawa?

Both islands have white sand and clear, pale water, but Okinawa is the far better place to swim. Jeju's best beaches are striking. Hyeopjae and Geumneung on the northwest coast look over shallow turquoise water to Biyangdo island, and at Hamdeok and Gimnyeong in the east black basalt breaks the sand into small coves. The sea is only warm enough from July to September, though, and for the rest of the year these are beaches for walking.

Okinawa's best water is on the outer islands. The Kerama bays on Tokashiki and Zamami and the long sands of Miyako lie over coral, and the sea stays swimmable for about half the year. Near Naha the beaches are tidied resort strands, so it pays to head north to Onna and Motobu or take a ferry out.

The food is equally good on both, and both are built on pork, but the cooking is different. Jeju grills its black pork at the table over charcoal, and its other pillar is the seafood brought up by the haenyeo: abalone porridge, sea urchin soup and raw conch. Tangerines turn up in everything, and much of the eating happens in cafés set in old stone farmhouses scattered along the coast.

Okinawa braises its pork into rafute and stir-fries it with bitter melon. It also has dishes like taco rice from the long American presence, and awamori to drink. The eating is more concentrated, around the Makishi Public Market and the izakaya lanes of Naha, whereas on Jeju the good places are often a drive apart.

Okinawa has more to see. It was the seat of a separate kingdom, and the Ryukyu court at Shuri, the royal tombs, the Shikinaen garden and the curving gusuku walls at Nakijin and Katsuren look unlike anything in mainland Japan. The memorials to the 1945 battle at Mabuni and Himeyuri add a serious second strand.

Jeju's heritage is humbler, the culture of a remote island rather than a royal one. It has thatched basalt houses at Seongeup, the Haenyeo Museum, the dol hareubang stone figures and the sober 4.3 Peace Park. All are worth a visit, but there are many novelty theme museums to skip, and the island fills fewer days of sightseeing.

Nobody picks either island for its nights, but Okinawa gives you more to do after dinner. On Jeju the going-out is almost all in Jeju City, and it follows the Korean pattern: barbecue and soju at the table, then on to a pub, and for a few people one of the town's handful of clubs. Base yourself around Seogwipo or on the quieter coasts and the evening usually ends with dinner, a beer by the sea or a chat in the guesthouse.

Naha's evenings run later and are easier for a visitor to join. The izakaya around Kokusai-dori pour awamori, Matsuyama keeps going into the small hours, and the old market lanes of Sakaemachi hide standing bars with room for only a handful of drinkers. Chatan's American Village feels the most Western, though Okinawa has even less of a club scene than Jeju City. Away from Naha and Chatan, the resort coasts go as quiet as Jeju's.

Both islands are superb for nature, but in opposite directions. Jeju's landscape is volcanic and on land. You can climb Hallasan, at 1,947m the highest peak in Korea, walk up to grassy oreum rims, watch the sunrise from Seongsan Ilchulbong and go underground in the Manjanggul lava tube.

Okinawa's best is underwater: turtles and coral gardens in the Kerama marine park, mantas off Ishigaki, and humpback whales from January to March. On land it has subtropical jungle in Yanbaru and mangrove rivers on Iriomote, but there are no mountains to climb.

On both, a day out mostly means another island, and Okinawa's are more rewarding. Taketomi, off Ishigaki, is a whole village of red-tiled houses and white sand lanes. Kudaka is a sacred island in Ryukyu tradition, and Bise's lanes run under tunnels of fukugi trees.

Jeju's list is shorter. You can cycle round Udo, walk among the barley fields on Gapado or stand at Korea's southern tip on Marado. Because the mainland is a flight away, the options end there.

Okinawa has the edge for children, mainly because of the sea. The Churaumi Aquarium, with whale sharks in its main tank, is a highlight of any family trip, and netted beaches and reef lagoons let even young children snorkel for much of the year.

Jeju is still very easy with children. It has shallow, sheltered water at Hamdeok and Hyeopjae, horse-riding farms, tangerine picking in winter and an easy walk into the lava tube. It also works outside the short summer. Both islands are safe and clean, and on both you will spend a lot of time in the car.

Jeju is the easier island to get around. It takes about an hour to cross, the roads are good, and express buses link Jeju City, the airport and Seogwipo. Most visitors still hire a car, and foreign drivers need an international driving permit.

Okinawa is really several trips in one. Naha has its monorail to Shuri, but the rest of the main island means a hire car in slow coastal traffic. Miyako and Ishigaki need a flight, and rough seas can cancel the small-island ferries.

Neither island is a shopping destination, and they offer different things. Jeju's shopping is duty-free cosmetics and luxury goods in Jeju City and at the airport, plus markets selling dried fish, omija tea and tangerine sweets, and a few studios selling basalt pieces.

Okinawa's strength is crafts. Look for yachimun stoneware from the Tsuboya quarter and the Yomitan kilns, colourful Ryukyu glass and stencil-dyed bingata cloth, which make better things to take home.

The two cost much the same, and on both the hire car and the summer season are what push the budget up. On Jeju, the Jungmun resorts and seafront rooms are expensive in July and August and in the Lunar New Year and Chuseok weeks. Guesthouses, noodle lunches and the free Olle trails keep a trip affordable.

In Okinawa, a stay based in Naha with day ferries stays moderate. Island flights, diving trips and west-coast resorts in Golden Week or the school breaks add up fast.

Here Okinawa is far ahead, because its music is still part of everyday life. On most nights in Naha, sanshin players and min'yo singers perform in izakaya until the room gets up to dance kachashi. The National Theatre Okinawa stages Ryukyu court dance and kumiodori, summer brings eisa drumming to the streets, and Koza has its own rock scene.

Jeju offers occasional concerts at its arts centres and haenyeo work songs at folk festivals. Otherwise there are only tourist dinner shows.

The two are equally restful, but they relax you in different ways. Jeju offers Korean bathing culture: jjimjilbang in both towns, large spas at Jungmun and a rare carbonated spring near Sanbangsan. Walks in the cedar forests and quiet villages inland fill the rest of the day.

Okinawa has no hot springs to speak of. Its calm comes from the pace of small islands like Taketomi and Kohama, where days slow to cycling and sitting in the shade. On both, the busiest places, Naha and Jeju's summer coast, are the least peaceful.