You can go there by boat from Vancouver ( across the Strait of Georgia ) or from the state of Washington ( across the Strait of Juan de Fuca ) . It is separated from the mainland of British Columbia by Johnstone Strait , and Queen Charlotte Strait on the northeast , and by the Strait of Georgia on the southeast , which along with the Strait of Juan de Fuca along its southwest separate it from the United States ( the Straits of Georgia and Juan de Fuca are now officially also part of the Salish Sea , which includes Puget Sound as well ) .