Rayakoski (Russian: Раякоски; Finnish: Rajakoski, Norwegian: Grensefoss; the Finnish and Norwegian name means border rapids, while the Russian name is borrowed) is a rural locality (an inhabited locality) in Pechengsky District of Murmansk Oblast, Russia, located adjacent to the tripoint between Finland, Norway, and Russia. Population: 238 (2010 Census).

The settlement of Rayakoski emerged during the construction of the Rayakoski Hydroelectric Power Plant in 1955 and 1956. The Muotkavaara border tripoint between Russia, Finland and Norway is located nearby.