Suomenlinna Sea Fortress is possibly Helsinki’s top tourist attraction. We spent our Christmas morning in Helsinki exploring this former naval fortress, with all its history, and thoroughly enjoyed ourselves.

The island is not only convenient to get to from Helsinki, but also easily accessible by foot, and has quite a few things to do.

The Suomenlinna Sea Fortress as seen from above

About The Suomenlinna Sea Fortress

Located just a 15-20 minute ferry ride from the heart of Helsinki, Finland’s capital city, lies the picturesque and historic Suomenlinna Sea Fortress. Although Suomenlinna today is home to some 800 residents, it once played a vital role in the defence of Finland, Sweden, and Russia. It was founded in 1748 on a cluster of islands off the coast of Helsinki and was added to the UNESCO list of World Heritage Sites in 1991.

The other walls of the Suomenlinna Sea Fortress

Built in the late 18th century by King Frederick I of Sweden, Suomenlinna was constructed as a defensive stronghold against the Russian Navy and played a significant role in the Great Northern War. Over time, it evolved into a military base and eventually, with Finland’s independence from Russia in 1917, it became a symbol of Finnish sovereignty.

Today, Suomenlinna is an open-air museum, showcasing its rich history through restored buildings, museums, and interactive exhibits. Visitors can explore the fortress’s grand fortifications, bastions, and casemates, as well as stroll through the beautiful parks and gardens. The island also features a range of attractions, including the iconic King’s Gate, the Suomenlinna Museum, and the stunning views of the Helsinki skyline.

Helsinki in the background, Suomenlinna in the foreground

Getting to Suomenlinna

Suomenlinna is easily accessible by a ferry from Market Square in Helsinki. The journey takes roughly 15 minutes, and the ferry runs all year round (even on holidays).

Or you could get the Helsinki Card, which includes entry to Suomenlinna along with 20 other attractions in Helsinki.

Welcome to Suomenlinna island

There is also a water-bus service that runs between Helsinki and Suomenlinna. However, unlike the ferry, the water-bus service only runs in the summer. The service also departs from Market Square but arrives at the south side of Suomenlinna, at Artillery Bay.

Artillery Bay quay, Suomenlinna

Getting Around Suomenlinna

Suomenlinna is small enough to explore on foot. The island is 0.8 km² in area, and it’s easy to cover all the attractions within a few hours.

Behind Piper’s Park – Suomenlinna

When you arrive at Suomenlinna, head to the information counter to grab a pamphlet. The pamphlet contains a map of the best route to take so that you don’t miss any major attractions. Luckily, all attractions on the island are also marked with visible blue signs.

One of the many buildings on Suomenlinna today

Here’s a quick video of from our visit.

Guided walking tours are available during the summer months and on weekends through the rest of the year.

Major Attractions on Suomenlinna

Once you’re on Suomenlinna take your time and explore the group of islands. These are a few major attractions that I think you don’t want to miss.

Suomenlinna Church

The gorgeous Suomenlinna Church, Helsinki

Once you get off the ferry, the Suomenlinna Church is the first main attraction that comes on the way. It was initially built to serve as a Russian Orthodox garrison church but was later converted into a Lutheran place of worship.

Front view of the Suomenlinna Church

The colours of Suomenlinna Church

Although we didn’t have a chance to step inside the church, it’s supposed to be quite beautiful inside.

Great Courtyard

The Great Courtyard of Suomenlinna is the main square of the island. It was built in the 1760s and badly damaged in the Crimean War in 1855. The tomb of Ehrensvard (the architect, artist, and creator of the Suomenlinna) can be found in the Great Courtyard.

Kustaanmiekka

Kustaanmiekka, Suomenlinna

My favourite attraction on Suomenlinna was the Kustaanmiekka. Until we stumbled into the area, we kept wondering why this island was called a sea fortress. It was here where we finally got to see the cannons of the original sea fortress, and the Russian defence line complete with sandbanks and artillery emplacements.

The Suomenlinna Sea Fortress

King’s Gate

King’s Gate, Suomenlinna

The King’s Gate is the iconic gateway to Suomenlinna. It is named after King Adolf Frederick of Sweden who had his ship anchored in this location while he of inspecting the construction of the fortress in 1752.

The inscription on King’s Gate, Suomenlinna

The gate is located at the southern end of Suomenlinna and is connected to the barracks. Artillery Bay, the area around King’s Gate with its high walls and small windows, makes you feel like you’re truly inside a fortress.

Museums

There are a total of six museums at Suomenlinna, located in different parts of the island. Although each museum sells its own entry ticket, during the summer one can buy a combined ticket for all the museums.

Although we didn’t get a chance to see all the museums, the ones that I would recommend are the Suomenlinna Museum and the Vesikko Submarine.

The Finnish submarine Vesikko – Suomenlinna

As the name implies, the Suomenlinna Museum is the main museum on the island. Here you can learn about the history of the sea fortress through a short film that runs every 30 minutes.

Top-down view of the Submarine Vesikko, Suomenlinna. Restored CV-707 submarine built in 1933 & open as a museum in 1973.

The Vesikko Submarine is a Finnish submarine that served in World War II. Visitors can enter the submarine and tour the cramped interiors of the vessel.

Suomenlinna — A Must-Do for Anyone Visiting Helsinki

We hope that you found our guide to the Suomenlinna Sea Fortress helpful in planning your trip to the island. Make sure that you check out our guide on the top things to do and see in Helsinki for more inspiration.

Also, if you happen to be in Helsinki during Christmas, we’d highly recommend visiting Suomenlinna. Unlike everything else in Helsinki, Suomenlinna remains open to tourists. In fact, there’s a fun Gnome Trail game that Suomenlinna around this time of the year.