Take a look beneath the surface. For a moment, everything is clear and bright. As you dive deeper, the water first turns greenish, then gradually dims. Near the bottom, you turn on your light. From this dimly lit world emerges the underwater Suomenlinna.

The Underwater Suomenlinna tour is a dive beneath the fortress's surface. Below the water, you’ll find an underwater world rich in cultural heritage. The tour focuses on fascinating underwater structures and shipwrecks from various periods of the fortress's history. Some of the sites are part of grand plans and are massive in size, while others are modest piles of wreckage on the seabed. When such a pile is identified and named, it becomes a part of the fortress's history, telling not only its own story but also about the events surrounding it. The tour also looks beyond Suomenlinna’s shores, with a visit to the wreck of the warship Kronprins Gustav Adolf.

Additionally, the tour provides a glimpse into the work of a marine archaeologist at Suomenlinna’s underwater archaeological sites.

The tour includes stops on four of Suomenlinna's islands, which you can visit in any order. The recommended starting point is the ferry dock. The stops are located as close as possible to the underwater sites they describe. The sites themselves are marked on the map with a special symbol. Photos and videos offer visual material and additional information about each site and its surroundings.

Be especially cautious in steep areas and near the water.