Preah Sihanouk Province lies in the southwest Cambodia on the Gulf of Thailand and is home to its only deep-water port, Sihanoukville Port. The port serves as one of the country's windows to the world. The province boasts several special economic zones, including Sihanoukville Autonomous Port, which has been jointly developed by Cambodian and Chinese enterprises.

In September 2019, China's Hainan Province established sister province relations with Cambodia's PreahSihanouk Province. In September 2026, Preah Sihanouk Province Vice Governor Sous Serey Sousdey visited Hainan. During this visit, Sous Serey Sousdey stated that they hope the connection between Hainan's ports and Sihanoukville port will provide many benefits.