The Morvan (a Celtic name meaning 'Black Mountain') offers an abundance of options to fans of outdoor activities. On dry land choose from walking (the park has more than 2500km of marked trails), mountain biking, horse riding, rock climbing and orienteering. On water, there's rafting, canoeing and kayaking on several lakes and the Chalaux, Cousin, Cure and Yonne rivers, along with excellent trout fishing in the River Méchet. Lac de Pannecière, Lac de St-Agnan and Lac des Settons have water-sports centres.
Guided walks of the park, some at night (eg to observe owls), are available from April to October, and there are children's activities in July and August. Boat tours are available at Lac des Settons.
In the mood for swimming? Head for Lac des Settons or Lac de St-Agnan, which offer 'beaches' (a loose term by anyone's standards).
The Morvan Visitors Centre has a comprehensive list of outdoor operators.