SIM Swap Scams in Thailand
Criminals hijacking Thai mobile numbers to intercept OTP codes and drain PromptPay and mobile banking accounts.
Part of: SIM Swap Scams
Last reviewed: 1 June 2026
SIM swap fraud in Thailand primarily targets PromptPay users — Thailand's instant payment system linked directly to mobile numbers — as well as users of major Thai bank mobile apps. Once a fraudster controls a victim's number, they can receive OTP codes for all linked financial services.
Thailand's three main carriers — AIS, DTAC (now True Move H), and True Move H — have implemented customer authentication measures, but social engineering and compromised carrier staff remain risk vectors.
How this scam works on Thailand
Fraudsters gather target personal data through phishing, data breaches, or social engineering. Armed with the victim's ID card details and carrier account information, they contact customer service or visit a store to request a SIM replacement, impersonating the account holder.
Once the SIM is active in the fraudster's device, the victim loses signal. Within minutes, the fraudster uses intercepted OTPs to log into Thai bank apps (Krungthai, SCB, Bangkok Bank) and execute PromptPay transfers. Because PromptPay is linked to phone numbers and transfers settle instantly, funds can be moved and withdrawn very quickly.
WhatsApp and Line account takeover is an additional consequence — enabling the fraudster to impersonate the victim to contacts and request emergency money transfers.
Common red flags
- Sudden loss of mobile signal without network issues
- SMS confirming a SIM card change you did not request
- Bank OTP SMS for transactions you did not initiate
- Line shows active session on an unfamiliar device
How to protect yourself
- Register a SIM security PIN with your Thai carrier
- Replace SMS OTP with app-based OTP for Thai banking apps where supported
- Enable PromptPay transaction limit settings in your bank app
- Contact your carrier and bank immediately if you lose signal unexpectedly
- Regularly review PromptPay and bank account activity through official apps
How to report it
- Contact your carrier fraud line immediately
- Call your bank fraud hotline and request an account freeze
- Report to Thailand's AOC 1441 and the NBTC (National Broadcasting and Telecommunications Commission) at nbtc.go.th
Frequently asked questions
How is PromptPay linked to my phone number and what risks does that create?
PromptPay allows you to register your bank account with your mobile number so people can transfer money to you just by entering the number. If a fraudster controls your SIM and triggers a bank password reset via SMS OTP, they can redirect your PromptPay to their account. Setting a carrier SIM PIN and using app-based authentication significantly reduces this risk.