Lake Gopło

Lake Gopło (pronounced roughly GO-pwo) is the largest natural lake in Kuyavia, a long glacial lake in central Poland, about 25 km from end to end. The town of Kruszwica on its northern shore is where you will find the Mouse Tower and the legend of the cruel prince eaten by mice. It makes an easy day out for anyone exploring the Piast Trail between Poznań, Toruń and Bydgoszcz: a boat trip, a lakeside stroll and a climb for the view.

What kind of lake is it?

Gopło is a ribbon-shaped lake formed by glacial meltwater, running north to south for roughly 25 km and up to 3.5 km wide. Its deepest point is 16.6 m. The surface covers about 21.5 sq km, though sources disagree slightly, and it ranks among the ten or so biggest lakes in Poland. The Noteć river flows through it, and the Ślesin Canal links it to the Warta, so it belongs to a network of waterways rather than being a closed lake.

Why people visit: a legend and a tower

In Polish folklore, the semi-legendary Prince Popiel was a tyrant who was eaten by mice in a tower on the lake shore, which opened the way for the Piast dynasty and the Polish state. Today the story is attached to the brick Mouse Tower in Kruszwica, about 32 m tall, with around 109 steps. The tower is actually part of a castle built around 1350 under King Casimir the Great, so it is centuries younger than the legend. The panorama over the lake from the top is the best reason to climb it.

Things to do at Lake Gopło

• Take a cruise on the "Rusałka" from the pier in Kruszwica. The ship has served on the lake since 1971.
• Walk the waterfront around the castle hill and the peninsula in the town center.
• Watch birds. There is an ornithological reserve on the lake, and the area is protected as a Natura 2000 bird site. The lake lies in the Nadgoplański Millennium Park, and it is home to the European catfish, the largest freshwater fish in Europe.
• Visit the Romanesque collegiate church and the tower on foot, a few hundred meters from the water.

Plan about two to three hours in Kruszwica for a cruise, the tower and a walk. Families with children will enjoy the boat, but the tower stairs are steep.

Practical information (as of October 2026)

• Lake access: free all year at the waterfront in Kruszwica.
• "Rusałka" cruises: April 15 to October 30, departing at 9:30, 11:00, 12:30, 14:30, 16:00 and 17:00. The ship sails only with at least 10 passengers, so some departures can be cancelled. Tickets cost PLN 35 (regular) or PLN 30 (reduced) in the 2026 season. Buy them at the kiosk by the pier; the tourist office does not reserve individual tickets.
• Mouse Tower: open daily 9:00 a.m. to 6:00 p.m. in the season, PLN 16 regular and PLN 14 reduced. It is closed from December to March.
• PTTK Kruszwica: +48 52 35 15 380. Signs and information are mainly in Polish; I could not confirm English-language services, so a translation app helps.

Late in October, check that cruises are still running, as the season is ending.

How to get there

Kruszwica is roughly 20 km from Inowrocław, about 70 km from Bydgoszcz and about 120 km from Poznań, the nearest large airport city. Driving is simplest. If you rely on trains or buses, check current timetables beforehand.

Nearby

Kruszwica's Romanesque collegiate church and the Mouse Tower are minutes apart. The wider Piast Trail leads on to Gniezno and Biskupin, and Inowrocław has a spa park with graduation towers.