Take advantage of the island’s bike-friendly terrain—there are few cars here and not even a single stoplight—with a rental ($25/day) from Piccozzi’s Garage & Bike Shop (Bridge Street; 631-749-0045). Cycle the four-and-a-half-mile length of the island to secluded Shell Beach, a narrow curl of shoreline that juts into Shelter Island Sound and is accessible only by unpaved Oak Tree Lane. In addition to having the beach to yourself, you can enjoy warm water, beautiful wildflowers, small plovers hopping along the water’s edge, and views of West Neck Harbor and the South Fork.
Retreat to the southeastern area of the island to explore the Mashomack Nature Preserve, an expanse of more than 2,000 acres that covers nearly a third of the island. Choose from a range of trails, which offer everything from a 30-minute introductory walk to a four-hour hike, and keep an eye out for ospreys and their gigantic nests as you navigate tidal creeks, woodlands, salt marshes, freshwater wetlands, and twelve miles of coastline.
Paddle around the island with Shelter Island Kayak Tours. Take a guided tour ($60 per person), or rent a kayak on your own (from $30) and take on the five-mile-round-trip Coecles Harbor Marine Water Trail. Just follow the buoy trail markers and look out for fiddler crabs, diamondback terrapins, blue herons, and egrets. If you pack a lunch, you can stop for a picnic on Taylor’s Island and explore its circa-1900 log cabin.