Ahvionkosket is a 1.2 km long free-flowing rapid area located in the Kymijoki River, protected under the Koskisuojelulaki and part of the Kymijoki Natura 2000 area.

The Kymijoki widens into a series of islands, with 12 islands in the Ahvionkosket area. The total drop of the rapids is around 2.5 meters. The area starts at Kuovinkallio in Ahvion village, where the river splits into three channels. The main channel runs through the dredged route of Päijänteensaaren and continues to Martinkoski, the largest rapid in Ahvionkosket, popular for kayaking due to its deep water and large waves. Smaller channels pass through Päijänteenkoski and Kuovinkoski. The area ends at Martin- and Kotokoski, where the river flows into a low-flow section leading to Kultaankoski.

The area also includes Myllypuro, a narrow stream with a historic mill that was moved in 2017 to a new location. The local wildlife includes species like the white-backed woodpecker, grey heron, and otter. The area is rich in mixed forest with birch, aspen, and spruce as dominant tree species.

Ahvionkosket is part of the Keski-Kymen special fishing area, and a resting spot is maintained by the city of Kouvola at Kuovinkallio.

More information.