Wellesley Island State Park offers the largest camping complex in the Thousand Islands region with 150 boat slips, a marina, four boat launches, and transient dockage (30 ft. max boat length, 3 ft. draft) for boaters.

The park features a sandy beach for swimming, a 9-hole golf course, cabin rentals, tent/trailer sites, and the Minna Anthony Common Nature Center with hiking trails; some secluded wilderness campsites are accessible only by foot or boat.

Amenities include a camp store, laundromat, bait/tackle shop, fuel, sewage pump out, and boat rentals (14-16 ft. fishing boats), with the park open year-round and campgrounds operational May-October.