When you come to San Juan Island you will see plenty of cyclists enjoying the weather and the scenery. And why not? Drivers are accustomed to bicyclists and there are plenty of places on the island to pull over and enjoy the view. Round trips tours on San Juan do involve some hills, but are still accomplished by many groups and families.
Earthbox Inn & Spa provides secure bikes racks to lock up (no bikes allowed in our guest rooms, sorry). Bring your won or rent a ride at Meat Machine Cycles, the local bike store, barely two minutes from Earthbox. They can help you out with any bike advice or route suggestions you might need.
Discovery Adventure Tours, also just down the street from Earthbox, also offers bike rentals in addition to bicycle touring packages.
Circuits to Roche Harbor on the North end or to the Westside overlooks are approximately 20 miles round trip and make for nice, half day trips. The flatter trip to the south tip of the island is similar in length although it does require backtracking on the same road for your return.