Mobile phone users can avoid international roaming "bill shock" now by dialling *106# to turn off all mobile data and global roaming settings when travelling.
International roaming lets you use your mobile phone to make calls and access the internet when overseas.
A collaboration with the National Broadcasting and Telecommunications Commission (NBTC) and all local mobile operators created a double-lock number aimed at curbing the growing epidemic of bill shock, where data charges pile up even if customers are not using their phone to talk or send messages.
Taking a smartphone overseas may be convenient, but data and roaming charges cost mobile customers over 100 million baht last year, said Takorn Tantasit, NBTC's secretary-general.
Bill shock from using mobile services in border areas ranked as the top complaint to the NBTC.
NBTC commissioner Prawit Leesathapornwongsa urged customers to turn off the automatic network searching mode when travelling to prevent their smartphones from connecting to other networks outside of their package.
Customers should occasionally check how much bandwidth capacity they have used as well as their remaining credit, he said.
"The *106# function is especially designed to help mobile users prevent bill shock," said Mr Prawit.
He said operators should set up measures and update their roaming systems to prevent customers from suffering excess costs.
The NBTC previously distributed a free handbook to the public explaining how they could prevent excessive charges when using mobile services abroad.
Mr Takorn added the NBTC is in talks with operators to set up a number for mobile users to prevent SMS spam, potentially available next year.