Thai telecoms regulator NBTC has instructed operators to comply with the new biometric SIM registration system by mid-December.
The regulator has issue an order that all new SIM card purchasers will need to register using the new system from December 15, the Bangkok Postreported.
Operators will be able to choose between requiring matching facial recognition against a purchaser's ID card or comparing fingerprints using a fingerprint reader.
The new system will replace the existing SIM registration system that has been operated by the NBTC since 2015. The regulator subsequently started deactivating unregistered SIMs.
According to the report, each face recognition unit will cost operators 500 baht ($15) while fingerprint systems will cost 9,000 baht per unit. The NBTC estimates that around 55,000 retail locations nationwide will have the new system ready by the December 15 deadline.
The first batch of fingerprint ID machines for the new system were sent to 30 trial locations in May, but an investigation found that only 2,000 SIM buyers had registered using the biometric system from these locations.
The regulator first decided to implement a biometric authentication system in late 2016, and late last month ordered all mobile operators to implement the system for new prepaid an postpaid SIMs.