Lake Saroma (サロマ湖, Saroma-ko), also Saroma Lagoon, is a coastal lagoon (hence a body of brackish water) in Saroma, Kitami, and Yūbetsu. It is located in Abashiri Quasi-National Park. By area, the lake is the third largest in Japan and the largest in Hokkaidō.

The name comes from the Ainu place name Saruomahetsu, meaning "place of many Miscanthus reeds and rushes".

Another nearby coastal lagoon is Notoro Lagoon, about 15 km (9.3 mi) to the east.