How do I transfer my retirement visa to my new passport in Thailand, and can I travel using both passports?

To transfer your retirement visa from your old passport to your new one, visit the immigration office where your visa was issued. It's advisable to complete the transfer before traveling again, as airport officials may be uncooperative if the opportunity was missed. Although some users report successful transfers at different immigration offices in Thailand, the process may involve a fee (around 500 Baht). You can use both passports for travel until your visa expires, but ensure the transfer is handled promptly to avoid issues.