Vallisaari and Lonna

Vallisaari

A former military island, closed to the public for most of its history and therefore left alone. What is there now is overgrown fortress works, moss, cliffs and summer cafés, with paths running through the middle of it. It is the island to choose if Suomenlinna felt too organised: there are fewer people, less signage and a great deal more nature. The crossing from Market Square takes about 15 minutes with JT-Line and the season runs 20 May to 12 September 2026, which is a narrower window than the sightseeing fleet's and worth checking against your dates.

Wear proper shoes. This is not a promenade, the ground is uneven, and the old works are exactly as you would expect old works left to the weather to be.

Lonna

Small, close and completely different in character. About seven minutes from Market Square, summer only, with a café, a restaurant and a public sauna on it. Lonna is the island you go to for an evening rather than an expedition — you can be out there and back inside a couple of hours, and the sauna is the reason most people go. If saunas on the water are what you are after, the sauna page covers how the whole business works.

Neither of them is Suomenlinna

This is the part that catches people. Suomenlinna is the big UNESCO fortress, it is served by the HSL public ferry on a city ticket, and it runs every day of the year. Vallisaari and Lonna are served by JT-Line, which is a separate operator with its own boats and its own seasons, from the same Market Square quay. Different gate, different ticket, different dates. The Suomenlinna page explains the fortress, and the island hopping page lists everything else in front of the city — Pihlajasaari from Merisatama and Ruoholahti, Harakka from Kaivopuisto, Isosaari about 40 minutes out.

Which to pick

Vallisaari for a half day outdoors, Lonna for an evening. If you only have time for one island in Helsinki and have never been, take the fortress instead; these two are what you do on the second visit or the second day, and they are better for having done the first.

Frequently asked questions