Coilessan is a designated camping permit area within Loch Lomond & The Trossachs National Park, situated on the west shore of Loch Lomond near Coilessan Burn.

Seasonal byelaws covering camping and firelighting apply here from 1 March to 30 September each year, during which anyone wishing to camp must book a permit in advance rather than wild camp freely.

The area falls within one of the park's Camping Management Zones, established to protect popular lochshores from environmental damage and antisocial behaviour. Permits can be booked up to four weeks ahead through the national park's online system.

Outside the March–September season, the standard Scottish Outdoor Access Code applies across the wider national park.