The SIM cards, carrying the DTAC brand, had not been removed from their plastic holders. They were found inside three bags on a cart wheeled across the border checkpoint by a Cambodian worker at 10am, said acting head of the Aranyaprathet custom checkpoint, Supattanapong Sae-lim.
The worker was released after claiming that he knew nothing about the SIM cards and was paid Bt50 to carry the three bags across the border to the Rong Klua Market on the Thai side.
Customs officials will contact the mobile phone operator to check whether the SIM card numbers are for Thai or Cambodian use before carrying out an investigation as to who was behind the smuggling and why.