Björkö by boat – a natural harbour and an inland lake in the outer archipelago

In the middle of Björkö lies Insjön, a clear lake of about 10.5 hectares that formed around 250 years ago when the land rose and the bay was cut off from the sea. The lake is up to 17 metres deep. A freshwater lake right next to the sea is a rarity in the outer archipelago.

A 2.3-kilometre nature trail signposted by Metsähallitus circles the lake, presenting the island's nature, history and scenery. Most of the route runs over treeless rocky terrain, and bridges and duckboards have been built over the most difficult sections. The lake is free of algae and has spots for jumping in from the rocks along its shore, so it is a popular place to swim. You can also snorkel in the clear water.

The island's original farm, Södergrannas, was restored after decades of neglect and opened to visitors in 2020. The restoration work received the Cultural Environment Deed award (Kulttuuriympäristöteko) in 2024. Ponies graze in the farmyard, and hens and cats roam around. From the corner of the café, a path climbs to Kumlet, the highest point of the island, where a lookout tower offers views over the outer archipelago.

The trip suits people interested in nature and outer archipelago scenery who want to spend a full day on the water. At a brisk pace the nature trail takes about an hour, but allow more time to take in the nature.

The harbour has a Metsähallitus information point, a campfire site with firewood and a nature trail, as well as dry toilets, waste bins and a septic emptying point maintained by Keep the Archipelago Tidy (Pidä Saaristo Siistinä ry).

In summer, Café Björkö operates in the farm's main house, serving homemade pastries and sweet and savoury snacks. There is no mains electricity on the island, and the café runs on solar power. The same building has a small shop and an archipelago museum displaying, among other things, a rope-making machine and a seal harpoon found on the farm. The farm also rents out a shore sauna by the hour and a hikers' cabin for three people for overnight stays. Check the café's opening hours, prices and bookings on the farm's website.

Let's keep Insjön clean together: no detergents, sunscreen or other chemicals may enter the lake. When using the sauna, use environmentally friendly washing products and keep them out of the sea water too.

Björkö is part of the Archipelago National Park, and Byviken is one of the national park's marked camping areas. Read the national park's regulations before your trip.

There is no fuel on the island. Refuel on the way if needed, for example in Nauvo. There is also a Seapoint boat fuel station nearby on Nötö. The Buster Magnum runs on 98E5.