Merimasku (Finnish pronunciation: [ˈmeriˌmɑsku]) is a former municipality of Finland. It was, together with Rymättylä and Velkua, consolidated with the town of Naantali on January 1, 2009.It is located in the province of Western Finland and is part of the Southwest Finland region. The municipality had a population of 1,513 (31 December 2004) and covered an area of 51.12 km² (excluding sea) of which 0.71 km² is inland water.