Church of St. Peter and Paul in Kaarma was built in 1260 in the style of early gothic, with a few romanesque details. It was partly rebuilt in the Middle Ages, partly due to its location on unstable ground. In the fifteenth century, a tower was added, and the interior was separated into two aisles and vaults were installed. The sacristy was also raised to the additional floor. The church was probably the first sacral building with a tower on the island of Saaremaa.
The original building consisted of a simple, aisleless nave, a short, narrower chancel, closed in the east with a straight wall, and a sacristy on the north side. In the 15th century, the church was enriched with a tower on the west side and vaults of the nave and the choir. The building was then transformed into a two-aisle structure. The room with a fireplace above the sacristy on the north side was unusual. It was originally intended as a refuge, but later likely served for pilgrims from nearby Gotland. The small windows of the sacristy still referred to the Romanesque period, unlike the larger Gothic, pointed-arched windows of the nave. This points to the sacristy as one of the oldest elements of the church, next to the chancel walls.
The church is a typical example of sacral buildings that were erected in the bishopric of Ösel–Wiek, although its original silhouette is slightly distorted by massive buttresses at the western corners. Inside the church, medieval frescos, a baptismal font from the 13th century and a sculpture of St. Simon from Cyrene from the mid-15th century, have been preserved. In addition, the pillars of the church are decorated with stone sculptures from the 15th century, representing a simple and suggestive style, derived from the influence of the abbey of Padise and the Dominican monastery in Tallinn.