Wellesley Island State Park offers numerous picnic areas with tables and grills, some overlooking the St. Lawrence River.

The park offers diverse birding opportunities, with over 200 species recorded. It features a variety of habitats including wetlands and forests that attract different types of birds throughout the year. Birdwatchers can spot waterfowl, songbirds, raptors and more during migration seasons or breeding periods. There are also guided tours available for those interested in learning about local avian life.

Within this rustic paradise, fishing is excellent--particularly for muskie in autumn. To accommodate boaters, the park has a full service marina and four boat launches. A sandy beach on the river offers great swimming and sunbathing and there is a recreation barn and 9-hole golf course on the Island. One of the main attractions of the park is the Minna Anthony Common Nature Center, which includes a museum, varied habitats such as wooded wetlands, 3 miles of shoreline and open granite outcrops, and miles of trails for hiking, cross-country skiing and nature education. The Nature Center provides educational and recreational programs for all ages.

One special feature at the nature center is the 1/4 mile handicapped trail that includes access to picnic tables and the seasonal butterfly house. Archery and muzzle loading are allowed in designated areas by permit only.