ON LAND
I recommend three main dive spots for a must visit. They are beautiful and easy to reach. I couldn't resist and went to the top of the volcano that rises in the center of the island. If you are lucky with weather, it's a good reason to test yourself for strength and look at the surrounding areas. The whole trip takes about half a day. I looked at the stadium where the World Football Championship took place, watching a local team game against rivals from the mainland. You can park right inside the stadium. And in general, parking everywhere is free or costs very little.
Every evening we visited local restaurants, many of which are near hotels and roads. Black pork meat (which they are very proud of) is in almost all of them and, of course, a large choice of seafood. Korean water beer and good soju are offered. You must try rice brew with added juice. The drink production history goes back 2000 years. Recently it is becoming popular again.
Everywhere there are mandarin gardens - the island's visiting card. There are tea plantations higher in the mountains. Museums are quite interesting.
The island is volcanic, so beaches, as we understand them, are almost absent.