Mobile (Cell) Phones
Best thing to do when you arrive in Thailand is to buy a Thai sim. The Mobile phone rates are so cheap. One of the main carriers is Advanced Information Systems (AIS) and their product is 1,2, Call. You can usually buy a sim with some credit for 250 to 300 baht. Last I used them though, you get a lot of SMS advertising. You can opt out if you call customer service. If you have an account (postpaid) service you can opt for a data sim.I connected my Sony Ericsson phone via USB to my laptop with the manufacturers software and had a reasonable wireless internet service. Great for checking email and surfing. Not so good for downloads etc.
Because of the advertising thing, we use True move prepaid sims. You normally only get one or two ads per day. True move are good. Only disappointment I had was intermittant service around Nong Khai & Tha Bo, especially indoors. The other problem was their english pre recorded messages are nearly impossible to understand.
A company called DTAC offer Edge high speed data around Bangkok and are rolling out the service to other areas now. Outside high speed coverage areas you will default to GPRS.
Hutch have a CDMA network. Australian CDMA phones (Telstra at least) roam very nicely in Thailand.
GSM digital mobiles roam well here but rates, even for calls in Thailand are horrendously expensive.
One great thing about the mobile network here is that you can use phone cards on some mobile company's SIMs.
A new premium overseas service is now operating available to AIS customers using a 005 prefix to call overseas on your mobile. Around 18 Baht per minute to Australia. However, you must register to use it.
I heard talk that it is not possible to call out of some Southern provinces only within them but I can't confirm it for sure.
According to a newspaper article late last year, 3G equipment is sitting in a warehouse here somewhere just awaiting regulatory approval.
Landlines
If staying with friends or family who have a landline, it's best to dial 009 prefix for international calls. They will get a separate itemised account from CAT Telecom. Last I looked, Australia was 7 baht per minute.
Last year I used a CAT Phone card and rates were 6 baht per minute to Australia. Keying pins all the time is a pain. If you have a fixed line available don't bother with the card.
Cheapest calls
I found the cheapest way to call out of Thailand was using Yahoo voice on my Notebook with a headset. last I looked, the rate was 1.5 US cents per minute to Australia but, you must have a decent internet connection to use it. I got away with dial up but you can expect a few problems now and then with dial up using voice.
