The Kalmar Art Museum (Kalmar Konstmuseum) occupies a purpose-built building in the old town and focuses primarily on Swedish art from the 19th century onward, with particular strength in work by artists connected to the southeast coast and the light conditions of the Baltic. The collection is manageable in size — a couple of hours at most — and the building is bright and well-designed.
The museum runs a programme of temporary exhibitions that often draw on the broader Swedish art world; check the current show before visiting, as the permanent collection alone may not justify a full afternoon. The café is a pleasant stop regardless. The museum is within easy walking distance of the castle and cathedral, making it a natural third stop on a day in the old town.