The provincial capital city of Haikou, with about 2.9 million residents, and two smaller towns, Ledong and Chengmai, locked down its residents on Monday, according to state media reports.
At least eight cities and towns, with a combined population of about 7 million, said their residents must not leave where they live except for necessary reasons such as grocery shopping or essential job roles.
They also suspended public transport services. The measures will stay in place for varying periods, with the shortest scheduled for a few hours, state media reports show.
About 25,000 tourists are stranded in Sanya, the hardest-hit city in Hainan’s outbreak and the island’s key tourist hub, as of Sunday.
Authorities declared Hainan’s beach resort city Sanya a Covid-19 hot spot on Saturday and imposed a lockdown, confining Chinese citizens and expatriates to their hotels.