Oppo, the Chinese smartphone maker that holds the fourth-largest global market share, will start selling its devices in Japan next spring, a source close to the company said.

Oppo's smartphones will be SIM-free when sold, meaning that buyers will be able to sign a contract with any carrier. The models made available in Japan will be from the company's mid-price range.

The company set up a unit in Japan in August and started operations in November. Oppo plans to officially announce its debut in the Japanese smartphone market on Jan. 31, the source said.

Oppo's upper-end models feature advanced swiveling cameras that give the brand a strong foothold in the youth market. They are priced from around $266 (¥30,000) to $620 (¥70,000) in China and elsewhere.

Oppo sold 99.4 million smartphones around the world in 2016, according to U.S. research firm IDC. In China, the world's biggest smartphone market, Oppo was the most popular brand by sales in 2016.