Semiahmoo Bay (Wikipedia) Semiahmoo Bay (/ˌsɛmiˈɑːmoʊ/ SEM-ee-AH-moh) is the southeastern section of Boundary Bay on the Pacific coast of North America in British Columbia, Canada. The bay is named for the Semiahmoo First Nation, who originally occupied the area. The Semiahmoo Peninsula borders the bay and was home to cannery operations. It is now home to the Semiahmoo Golf Resort.