Vallisaari is a former military island that was opened to the public in 2016 after being closed for 200 years — a 33-hectare nature reserve and heritage site in the harbour archipelago that has been reclaimed by forests, wildflowers, and the rare species that thrived during two centuries of human absence. The island is a 10-minute ferry ride from the Market Square (or Suomenlinna) and provides the most unexpected nature experience accessible from central Helsinki.
The military history is visible in the abandoned fortifications, ammunition stores, and barracks that were part of Helsinki's harbour defence system from the early 19th century onward. The buildings are deliberately not restored — they're left in various states of picturesque decay, with trees growing through roofs and wildflowers colonising parade grounds, creating a post-military landscape that is part nature reserve, part time capsule.
The island's vegetation is remarkably diverse for its size — the 200-year closure allowed plant communities to develop without human interference, and botanists have recorded over 400 plant species, including several that are rare in mainland Finland. Walking trails cross the island through forests, meadows, and along the rocky shoreline, and the views from the eastern cliffs — across the open Baltic toward Estonia — remind you that Helsinki is a maritime city sitting at the edge of a very large, very cold sea. Vallisaari is open from May to October and has a café but no other facilities, which keeps it wild in a way that Suomenlinna's managed accessibility doesn't allow.
Verified Facts
Vallisaari was closed to the public for approximately 200 years
The island opened to the public in 2016
Over 400 plant species have been recorded on the 33-hectare island
The island is open from May to October
Get walking directions
Helsinki, Finland
