St Mawes is a village on the end of the Roseland Peninsula, in the eastern side of Falmouth harbour, on the south coast of Cornwall, England. The village, formerly two separate hamlets, lies on the east bank of the Carrick Roads, a large waterway created after the Ice Age from an ancient valley which flooded as the melt waters caused the sea level to rise. The immense natural harbour thus created is claimed to be the third largest in the world. St Mawes was once a busy fishing port, but the trade declined during the 20th century and the village now serves as a popular tourist location, with many properties functioning as holiday accommodation. The village is in the civil parish of St Just in Roseland and lies within the Cornwall Area of Outstanding Natural Beauty (AONB).

The Roseland Peninsula, or just Roseland, is a district of west Cornwall, England. Roseland is located in the south of the county and contains the town of St Mawes and villages such as St Just and Gerrans. It is a peninsula, separated from the remainder of Cornwall by the River Fal.