The way international roaming works with 1-2-Call is a little bit complicated. From the country where you are roaming, you dial an access code (sorry, can't remember, but it will be texted to you in every country you roam in), enter the mobile number of the person you wish to call in Thailand. That person will then receive a text asking if s/he would like to receive your call. If s/he answers yes, your telephone will ring and you can commence your roaming call. You pay for the toll charges. The other party pays only for air time. I've only tried this with the other party also a 1-2-Call customer. I don't know how this works if the called number is land line.