The new rules require users to either have their fingerprints verified or their faces scanned.
The regulator first launched the system in June in Thailand's troubled south where a separatist insurgency has persisted for more than a decade, killing more than 6,500 people since 2004.
Officials say insurgents in the largely ethnic Malay Muslim provinces of Yala, Pattani and Narathiwat have used pre-paid SIM cards to trigger bombs.
Biometric registration in the south was adopted for national security reasons but elsewhere in Thailand it is aimed at mobile banking security, regulatory official Takorn Tantasith told a news conference on Nov 6.
"This is not aimed at tracking users, but enhancing security, especially in case of mobile payments," said Takorn, the secretary-general of the National Broadcasting and Telecommunications Commission.
Similar biometric systems are already in use in Bangladesh, Pakistan and Saudi Arabia.
From Dec 15, Thais will be required to register new SIM cards, both pre-paid and post-paid, at service centres and retailers across the country, which will be equipped with biometric tools, he added.
SIM cards for post-paid accounts are now registered on purchase, while pre-paid SIM cards can be bought with no identification.
To register a new SIM card, users' fingerprints will be matched against the data stored on their national identification cards, identical to that in the government's central citizen database, Takorn said.
Mobile operators will shoulder the cost of card readers, which range from 500 baht (RM63.76) to 9,000 baht (RM1,147.74), he added.
The verification process might alternatively involve facial scans, depending on the equipment available.
After verification, service centers will send users' data to mobile operators for record-keeping, without storing any information on-site, Takorn said.
Foreigners buying SIM cards in Thailand will have their faces scanned and matched against their passport photographs. — Reuters