Kraków's cycling infrastructure has developed considerably in recent years. The city has a network of marked bike paths, and several of the most interesting routes extend well beyond the city limits into genuinely varied terrain.
The Vistula Boulevards route is the obvious starting point. It runs along both banks of the river through the city centre and extends east toward Niepołomice. On a clear morning, the stretch past Wawel Castle is genuinely beautiful. The surface is mostly smooth tarmac, making it accessible for all bike types including city bikes.
The Niepołomice Forest loop is a different proposition. About 25km from the city centre, it's a flat route through a large lowland forest. The forest roads are well-marked and mostly gravel, suitable for hybrid bikes. The route passes through the village of Niepołomice itself, where there's a royal castle worth a brief stop.
South of the city, the Wieliczka direction offers a more demanding ride with some gradient. The reward is the option to visit the salt mine at the end. Note that the return journey is uphill if you've descended to Wieliczka, so plan accordingly or take the train back.
Seasonal notes
Spring (April-May): the Vistula paths can be busy on sunny weekends. The forest routes in Niepołomice may have some muddy sections until mid-May. Summer: all routes are in good condition. Start early in July and August to avoid heat on exposed sections. Autumn: excellent conditions through October. November can be wet and the gravel routes become muddy.