You can drive to Manitoulin Island via the Little Current Swing Bridge which carries Highway 6 over the North Channel of Lake Huron in Northeastern Manitoulin, Ontario.
To reach the Swing Bridge, from Highway 17 (Trans Canada Highway) between Sudbury and Sault Saint Marie, turn on to Highway 6 for Espanola and continue for 50 kilometers (or 31 miles) towards Little Current. The bridge is usually in the closed position to allow highway traffic to cross, except during summer, when it swings open for the first 15 minutes of each daylight hour to permit passage of boating traffic. There is no weight restriction on the bridge.
Alternatively, vehicles can be taken on the daily ferry service between Tobermory on the Bruce Peninsula and the South Baymouth terminal on Manitoulin Island, with a crossing time of up to 2 hours.