The area of Merikarvia was initially held by the people of Sastamala (Karkku and Tyrvää) as hunting grounds, which is the origin of the Swedish name Sastmola.

[5] The birth of the earliest villages in Merikarvia - Kasala, Riispyy, Alakylä, Ylikylä and Köörtilä - is dated to between the 13th and 14th centuries.

[9] The first church in Merikarvia was built in 1776 and was named after the queen consort of Sweden at the time, Sofia Magdalena.

Like neighboring Ahlainen (Vittisbofjärd), Merikarvia was originally predominantly Swedish-speaking due to the Swedish settlement in the area during the Middle Ages.

The Swedish language mostly disappeared from the area in the early 20th century, mainly remaining in the village of Kasala (Kasaböle) near the border with Sideby.