James Island State Park is a secluded island off the western coast of Decatur Island. The island can easily be accessed from Lopez Island, and it can also be reached by crossing Rosario Strait from Fidalgo Head, which avoids the hassle of taking a ferry. Either route involves possible tide rips, but the route from Fidalgo Head involves a 3 mile open water crossing with possible shipping traffic.
James Island offers three Cascadia Marine Trail sites as well as 10 other campsites throughout the island. A mile and a half of trails crisscross the island, offering ample forests and beaches to explore dotting. The northern side of the island is designated as a natural forest area, and it is closed to the public, but the rest of the island's recreational trails are open to explore and provide great views of the San Juan Islands from the western side of the park.