In September, China's industry and information technology ministry issued a notice on "safeguarding the legitimate rights and interests of citizens online", which laid out rules for enforcing real-name registration.
The notice said telecom operators should use "artificial intelligence and other technical means" to verify people's identities when they take a new phone number.
A China Unicom customer service representative told AFP that the December 1 "portrait matching" requirement means customers registering for a new phone number may have to record themselves turning their head and blinking.
"In next steps, our ministry will continue to...increase supervision and inspection...and strictly promote the management of real-name registration for phone users," said the September notice.
While researchers have warned of the privacy risks associated with gathering facial recognition data, consumers have widely embraced the technology -- though China saw one of its first lawsuits on facial recognition last month.
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In addition to mobile users, the Twitter-like Chinese social media site Weibo was forced to roll out real-name registration in 2012.
Oversight of social media has ramped up in recent years as part of the Chinese government's push to "promote the healthy, orderly development of the Internet, protect state security and public interest".