The Aude offers gentle kayaking through the city and out into the surrounding plain, with the walls of the Cité visible from the water for much of the trip. The river is calm in summer; spring meltwater from the Pyrenees makes it livelier in March and April.
Operators on the south bank, including La Boulal at Alairac (tel. 04 68 26 93 56), rent kayaks and run guided trips. A half-day descent from upstream of the city back to Carcassonne is the standard outing.