Cetan/Thurston Bay Conservancy was designated in 2007 and is adjacent to Thurston Bay Marine Park. It is located on the northwest side of Sonora Island in Johnstone Strait. Cetan/Thurston Bay Conservancy connects the two separate portions of Thurston Bay Marine Park and provides additional sheltered anchorage and recreational opportunities for boaters traveling the popular Inside Passage.
Access to the Conservancy is by boat, kayak or canoe only. There are no developed facilities in the Conservancy, although random camping is allowed. Visitors can go swimming, fishing, hiking or paddling, or explore the small, pretty beaches dotting the rocky shoreline. An unmaintained trail leads to Florence Lake, ideal for peaceful swimming, fishing and paddling.