In short
Jeju is a volcanic island dominated by Hallasan, one thousand nine hundred and fifty metres, the highest peak in South Korea. Its lava tubes and cones are World Heritage.
The haenyeo, free-diving women who harvest shellfish and seaweed without tanks, often well past sixty, are on UNESCO's intangible heritage list.
What it really costs
Jeju is dearer than mainland Korea: everything comes by boat and the island lives off domestic tourism.
A car is essential: buses exist but the sites are scattered across an island seventy-three kilometres long.
What nobody tells you
The Olle trail runs four hundred and twenty-five kilometres in twenty-seven stages around the island. It is the best way to see it and almost no foreign visitor knows.
Climbing Hallasan requires a compulsory online booking on both trails leading to the crater, with a daily quota.
The island is the Korean honeymoon destination and fills up during national holidays. Outside those, it is quiet even in summer.