The church's vaults were added later than the original nave and were richly painted towards the end of the medieval period, reportedly by an artist known as the Rinkabymästaren, also associated with the so-called Vittskövle group. The paintings depict biblical scenes in a medieval style, apparently copied from German woodcuts rather than drawn from local inspiration. At some point in the 1600s or 1700s the paintings were limewashed over, before being rediscovered and uncovered in 1928; the Swedish History Museum has described them as well preserved but somewhat faded and damaged during that process.
A separate restoration in 2003 uncovered further wall paintings in the nave, applied almost directly onto the brick and possibly dating from the 1200s. Fragments of these remain visible today, including near the astronomical clock and, more clearly, behind the wall facing the sacristy, where faint faces can be made out.
Unusually, Rinkaby church has never had a tower. Its bell was originally housed in a freestanding wooden bell frame; a land survey map from 1751–1753 shows this standing in the eastern part of the churchyard, but by 1845 it had disappeared. This suggests the current roof turret was added sometime between 1753 and 1832.
Among the furnishings, the sandstone font is thought to date from around 1200 and is linked to the so-called Vitaby group of stonework. The pulpit and altarpiece structure date from the late 1600s, the latter topped with the monogram of King Charles XI. The altarpiece painting, depicting the Passion of Christ, is said to have been painted in 1695 by Eric Gelliers. Two bells hang in the church; the smaller is the older, cast in the 1400s, while the larger dates from 1695.
The present organ was built in 1904 by Johannes Magnusson of Gothenburg, with mechanical action and pneumatic wind-chests, and was later modified and enlarged in 1980.