Sidney Island. Sidney Island is a private island with 12 miles of sandy beach. Sidney Island is in the Gulf Islands near Victoria in British Columbia Canada in the Pacific Northwest. Real estate for sale on private island. Offering some of the finest waterfront property in the world with breathtaking views. Plus 1500 acres common with no public access. marina, 2600 foot airstrip, seasonal ferry. private island, Sidney Island, Sidney Spit, Sydney Island, Sydney Spit, Marine Park, Gulf Islands, Sallas Island, Sallas Forest, waterfront, beach, sandy, Victoria, Sidney, British Columbia, Canada, outer islands.