The Nakdong river as it all, miles and miles of dedicated cycling paths, boring stretches, hills to climb, lots of nature, countryside and endless river scapes, a little bit of off road with a random temple in the hills, camp sites, resting platforms and lots of cyclists. This path can sometimes have a lack of frequent shops or towns, so it's recommended to plan for that or to fill up when you have a chance.
Recommended as one of the top 3 most scenic and enjoyable paths in Korea. Mostly flat, with endless changing coastal landscapes, small quiet roads and shops and cafes all along the way. Each side has something interesting, wind-mills, waterfalls, beaches, dramatic cliffs and more. Jeju is a real treat to cycle.
Another small river that belongs in the top 3 routes of Korea. Very flat, beautiful natural untouched river and mountain scenes and compared to the other routes there are very few cyclists, which means you have the beauty and tranquility all to yourself.
Yeongsang river path will probably rank as one of the least popular. Ater the beauty of the bamboo and meta sequoia city of Damyang it is filled with long monotonous stretches of cycle path next to a river, sometimes with 50km without a town or shop. Very little shade or points of interest. Near the Mokpo end there are some nice stretches and some beautiful hill climbs.
Han river (World cup park to Pangyo)
Bukhan river (North Han, Seoul to Chuncheon)
Never a dull day on the East coast route, more hills than you would expect or hear of, forest paths, beach paths, river paths, barbed wire and beautiful coastal towns to keep you company. More off road or uneven path surfaces than expected, including some very steep stairs, but you will never be bored by the view and will never know what awaits around the next corner.