Katanpää by boat – a fortress island in the Bothnian Sea National Park

Katanpää was already used as a naval harbour in the 19th century. Its location was strategically important, as it made it possible to monitor all three coastal fairways crossing the Archipelago Sea. The island has also served as a prison island.

The Katanpää fortress was built in the 1910s, during the reign of Tsar Nicholas II. It was the northernmost part of the largest fortress chain in the Baltic Sea, Peter the Great's Naval Fortress, and it is the best-preserved part of the chain in its original form. Alongside the guns and other buildings, the last known tsarist-era wooden water tower has survived on the island; water was led from a 60-metre-deep borehole to the sauna in the barracks area.

The Finnish Defence Forces carried out extensive renovation work on the island's old buildings in the mid-1980s. Today Katanpää is a culturally and historically valuable sight visited by thousands of people every year, and the southernmost visitor destination of the Bothnian Sea National Park, established in 2011. The fortifications are protected under the Antiquities Act, so move around them with care.

The trip suits anyone interested in history and nature, and groups who want to spend a full day walking, enjoying the sauna and exploring the island's fortifications.

The island also has facilities for larger groups: the restaurant for pre-booked groups seats up to 50 people, and events for up to a hundred people can be held in the gun hall.

The harbour on Katanpää is sheltered and has 80 guest berths with buoy moorings. The depth is 2–6 metres. Day visitors have their own boom berths, and the harbour also has a separate ship jetty for cruise traffic and larger boats, as well as one berth for mooring alongside on the T-jetty. Moor according to the harbour's instructions.

The jetties have electricity and water, and the harbour has a shower and toilet. A septic tank emptying point is nearby and open to everyone. A guest berth includes electricity, water and use of the barbecue shelters, and day visitors pay a separate day fee.

The harbour office is next to the harbour café. There you pay the harbour fee, book the sauna and register if you are staying overnight. The harbour and saunas do not take advance bookings, so berth availability cannot be guaranteed.

The harbour and harbour café are open in summer from the beginning of May until late September. On the nautical charts, the harbour is on chart 723 of chart series D, harbour number 920.

The harbour café is the heart of the island. In summer it serves soup lunches and home-made pastries with fresh coffee, and the spacious terrace seats a hundred people. In addition to coffee and soft drinks, the drinks selection includes wines and craft beers.

For groups there is a restaurant for pre-booked meals, which has served as a laundry and a soldiers' canteen, among other things, and seats up to 50 people. The granite Marski's Cellar (Marskin kellari) seats 6–20 diners. President Martti Ahtisaari was served dinner in the cellar when he visited the island during his presidency.

There are three saunas for hire right next to the harbour. The two smaller ones take about ten people and the largest 20, and the largest also has a fireplace room and a terrace with a fireplace. You can go straight from the sauna into the sea. Book a sauna at the harbour office or café.

In addition to the roads and paths from the fortress era, the island has two marked trails of about one kilometre: the Shore Trail and the Ancient Burial Loop. Ask at the harbour café about guided tours. To protect nesting birds, keep to the marked trails from 1 May to 15 July.

The island has campfire sites, cooking shelters, a tent site, a drinking water point and dry toilets. During forest and grass fire warnings, fires may only be lit at campfire sites with both a roof and a chimney. Take your rubbish home with you: the national park follows the principle of litter-free hiking.

Plan your refuelling in advance. In Kustavi you can refuel, for example, in Lootholma and Vuosnainen. The Buster Magnum runs on 98E5.

On Katanpää you can stay, for example, in the Pump Room (Pumppuhuone), an apartment completed in 2025 at the top of the old water tower. Its private balcony looks out over the Bothnian Sea National Park, and breakfast at the harbour café is included.

The Officers' House has two apartments with their own kitchen, shower and toilet. Combined, they sleep up to 14 people, and residents can use a gas grill in the yard. The island also has a tent site. Register as an overnight guest at the harbour office.

When you rent the Buster Magnum from us for several days or even a week, you can stay the night and continue your trip the next day. Book accommodation directly with the provider.