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Welcome to Suomenlinna

Suomenlinna is a historical maritime fortress and one of Finland’s most popular sights. It attracts more than 700,000 visitors every year.

Suomenlinna Sea Fortress

Visiting the maritime fortress

  • Suomenlinna has something for everyone – walls, cannons, tunnels, a submarine, museums, cafés, restaurants and even a brewery!
  • Many find the 15-minute ferry crossing to the fortress the most enjoyable part of the visit. It offers you a unique chance to see and photograph Helsinki from the sea.
  • The fortress is one of seven Unesco World Heritage sites in Finland.

Visitor Centre

The Visitor Centre staff are happy to give you information on places of interest and open restaurants and cafés. Suomenlinna information leaflet with a map is available in different languages.

To get a good overall picture of life in the fortress in the 18th and 19th centuries, watch the Suomenlinna Experience short film in Suomenlinna Museum, located in the middle of the fortress in Suomenlinna Centre, and take a guided tour.

Plan your visit

Are you planning on visiting Suomenlinna in the summer or winter? Would you like to take a guided tour or explore the fortress on your own? Allow 1-2 hours in the winter and 2-4 hours in the summer for your visit. Go to the Plan your visit page.


The fortress was built in the 18th century to fortify defences at the eastern part of the Swedish Empire. After the fortress fell under Russian rule at the beginning of the 19th century, its role was to guard the shipping channels to St. Petersburg.

The Swedish maritime fortress helped Helsinki to grow into a significant city which became the capital of Finland in 1812 when the country was an autonomous grand duchy within the Russian Empire. More…


The fortress was built on virtually barren islands. Today, nature in Suomenlinna is extremely diverse.

The scenery ranges from parks, yards and herb gardens to natural beaches, wild meadows and earth-filled sandbanks.

The islands are surrounded by sea and bordered by cliffs and sandbanks. More…

Fly over the fortress

Suomenlinna consists of a group of islands. Take an aerial tour of the fortress by helicopter. The clip lasts 4 minutes and 39 seconds. Below is a list of the structures shown in the clip in order of appearance.

00:45 Finnish Naval Academy
01:05 Main pier
01:35 Service pier
02:00 Open prison
02:15 Submarine Vesikko
02:30 King’s Gate
02:30–03:30 Kustaanmiekka walls and sandbanks
03:50 Dry dock
04:15 Church

Suomenlinna in figures

Inscription on a cannon
  • 8 islands
  • 6 kilometres (3.7 miles) of walls
  • more than 100 guns and cannon barrels
  • 290 buildings
  • 6 museums and 9 restaurants
  • 700,000 visitors every year
  • 850 residents
  • UNESCO World Heritage Site since 1991
  • Construction started in 1748