The Straight of Juan de Fuca is a 153 km (95 miles) long channel of water that lies between southern Vancouver Island and the Olympic Peninsula in Washington. It encompasses what is known as the Salish Sea and extends out to the open Pacific Ocean. All vessels coming from the Pacific Ocean and heading to ports in Victoria, Vancouver, Seattle, the Inside Passage and other smaller locations must pass through the Straight of Juan de Fuca. It is known as the busiest shipping lane on the Pacific seaboard. This channel can experience rough seas due to exposure to westerly winds and waves from the open Pacific.

The straight acts as a passageway for many species of migrating salmon moving from the ocean to freshwater rivers to spawn, the Fraser River near Vancouver being the largest spawning river for salmon in the area. Resident orcaʼs diet mainly consists of salmon, so from April until November, Southern Resident Orca feast on the salmon coming through the Straight of Juan de Fuca. The Straight also acts as a resting ground and final feeding area for dozens of migrating humpback whales from late August until December.