The Coast Forest is an area connecting Hayakawa Village and the Frosty Forest with the rest of the map. You can get to the Coast Forest by following the path from Hayakawa Village through the Frosty Forest. It is a green forest with a seemingly tropical climate. When you enter this area, you can hear many birds.
The Coast Forest contains a demon hideout, and three trainers; the Sun Breathing trainer Tanjiro Kamado, the Water Breathing trainer Sakonji Urokodaki, and the Thunder Breathing trainer Jigoro Kuwajima (known in-game as Kujima.) This forest also has one of the two bodies of water in the entire game.