Kidston Island serves as a natural breakwater for Baddeck Harbour. A lighthouse was built on the northeast end of Kidston Island in 1875 to guide mariners through the wider entrance to the harbour, but this light was not visible to mariners approaching Baddeck using St. Patricks Channel, which runs between Baddeck and Little Narrows. To mark the southwest approach to Baddeck Harbour, a lighthouse was placed on the west end of Kidston Island in 1976. This white, fibreglass tower is marked by two red bands and displays a flashing red light.
Sailing Directions for Cape Breton provides mariners the following information on Baddeck Harbour:
The favoured entrance into Baddeck Harbour is the channel NE of Kidston Island from Baddeck Bay. Lights are situated on both ends of Kidston Island. The NE light is a white square tower at an elevation of 13.3 m. The SW light is a white circular tower with two red bands. Baddeck Harbour has good holding ground of mud and sand.
- Lighthouses & Lights of Nova Scotia, E.H. Rip Irwin, 2003.