The Kazmierz Sosnowski Main Beskid Trail (Polish Główny Szlak Beskidzki imienia Kazmierza Sosnowskiego, "GSB") is a long-distance trail marked in red that leads from Ustroń in the Silesian Beskids to Wołosate in the Bieszczady Mountains.

Covering the highest parts of the Polish Beskids, it crosses peaks such as Stożek Wielki (Velký Stožek in Czech ), Barania Góra, Babia Góra, Polica, Turbacz, Lubań, Przehyba, Radziejowa, Jaworzyna Krynicka, Rotunda, Cergowa, Chryszczata, Smerek and Halicz as well as towns such as Ustroń, Węgierska Górka, Jordanów, Rabka-Zdrój, Krościenko nad Dunajcem, Rytro, Krynica-Zdrój, Iwonicz-Zdrój, Rymanów-Zdrój, Komańcza, Cisna and Ustrzyki Górne.

The route of the western part (Ustroń-Krynica) was designed by Kazimierz Sosnowski and it was finished in 1929.

It was completed 1935 and it led to Chornohora which, at the time, was located within the borders of Poland.

The current fastest known time on the trail belongs to Kamil Leśniak, who covered the trail in 93 hours, 42 minutes, and 22 seconds,[4] beating the prior record by just under two minutes.