Karl Johanslussen

Karl Johanslussen is a lock in the Slussen district that connects Lake Mälaren to the Baltic Sea and handles hundreds of boats daily. The structure spans roughly 75 meters in length and 10 meters in width, built from reinforced concrete to safely guide large vessels through.

The current lock opened in 1935 and represents the fourth structure at this location, following an original lock built by Queen Christina in the 17th century. Since then, this passage has remained a vital connection between the inland waters and the Baltic Sea.

The lock area transformed from a commercial shipping route to a focal point for pleasure boats and sightseeing vessels in the 1920s.

Visitors can watch the lock operation from various viewpoints around the Slussen district, particularly from the paved areas on both sides. It is best to visit in good weather, as heavy rain or fog may limit visibility of the vessels passing through.

The lock uses a specialized gate system that operates independently of water pressure, setting it apart from traditional lock designs. This feature allows for more reliable and efficient operation regardless of water level differences between the lake and sea.