Because Sansha's jurisdiction comprises island groups that several nations besides the PRC claim as their own, the "city".

In 1974, taking advantage of the withdrawal of the American troops from the Vietnam War, China invaded the Paracel, which Vietnam calls Hoang Sa, Islands.

The United States Department of State also concerned the establishment of the city of Sansha in late July 2012. The chair of the US Senate Foreign Relations East Asian and Pacific Affairs Subcommittee, Jim Webb, also made a statement regarding Sansha and questioned whether the city's creation was a violation of international law.

China's sweeping claim of South China Sea under their 9-dash line purportedly historical boundary is illegal and is creating tension among nations. Google maps showing this is part of China gives credence to what is plainly a territory grab that peace loving nations should stand against.