I used service of several small 3G providers in Bangkok. In Panthip plaza sellers sometimes sell their simcards as disposable. Don't remember the name of the provider I used, but even iFox who sells 3G modems has its own 3G simcards.

Are they present in other cities? Because, as I get, most of them use networks of big guys.

You are probably referring to TOT's MVNOs:

IEC http://www.iec3g.com/web/home.php

MoJo http://www.mojo3g.com/

IMobile 3GX http://www.i-mobile3gx.com/main/

IKool http://www.i-kool.net/th/index.php

365 http://www.365.co.th/store/

It looks like iFox resells TOT 3G and CAT CDMA, as separate services.

You can use these wherever TOT has service, which is many, many places now; it used to be just metropolitan Bangkok.

http://www.i-bkk.com/ilocation/viewer/

http://www.thaivisa....ost__p__4208378

http://www.thaivisa....ost__p__5054114

Thanks, but can you tell, which one has cheapest prices for the traffic? As I remember, I used IEC, from my calculations I got that I can spent 2000 baht for 25 Gb of traffic, but I can't find such prices at their website now.