Nearly 20 million prepaid mobile phone numbers can expect to be cut off after Friday's deadline imposed by the national telecom regulator.
The National Broadcasting and Telecommunications Commission (NBTC) expects 65 million prepaid mobile users to register their personal information under the regulator's circular, effective Saturday.
The 20 million unregistered numbers are believed to be inactive users, said NBTC secretary-general Takorn Tantasith.
The regulation governing the registration of prepaid SIM cards is to prevent criminals that use unregistered SIM cards from easily exploiting the numbers for illicit activity. It also seeks to redress the rampant growth of prepaid subscribers, many of whom are virtual, causing a waste of phone number resources and misuse of prepaid SIM cards.
The cabinet approved the regulation earlier this year as part of the national security agenda. From Friday, those failing to register subscriber information will no longer be able to use outbound mobile calling and data services. They can receive incoming calls and SMS messages for one more month.
"We believe an additional 5 million prepaid users will register their numbers during August after they experience the cut-off," said Mr Takorn.
He acknowledged that the NBTC could not bring all existing prepaid numbers into its registration system, as 20 million numbers are believed to be inactive.
Thailand has 105 million mobile subscribers, with 90 million being prepaid.
The NBTC recently spent 40 million baht to promote its prepaid registration campaign, offering 50,000 service points to assist users.
From Feb 1 next year, mobile operators will be fined 80,000 baht a day if they activate new prepaid SIM cards without registering them.