I'm sorry for asking a question similar to what has been discussed elsewhere in this forum, but I can't find an answer that's quite in response to what I'm looking for. After 2 hours of research... time to just ask.

I am going to be in BKK for 3 days in December. I have an unlocked iPhone 3GS that I use when I travel. That phone, you may know, operates on the 850 and 1900 Mhz bands, but not the 900 Mhz.

My primary (indeed, my sole) concern is for data usage amounts and speeds. I will be surprised if I make a single phone call or a single text. I thought I had pretty completely settled on the Happy SIM, but when I went to the carrier's page, I was disappointed in the offer. It seems the Smartphone SIM gives you 300MB of data, but only for use over 6 months, thus 50 MB per month. While 50-100 MB per day would probably do me, 50 for those three days certainly would not.

I read elsewhere about a AIS 12Call SIM that gives you 1GB over a month for a good price, but that's only on 900 Mhz, so no good for me. That's the kind of plan I'd love to have, as long as the speed was good. I have relatively high data uses, and I don't want to be hunting around for wifi. I use my iPhone as a MyWi so it drives data on other devices, which is why I need that much data.

So the bottom line question is for a 3G SIM card with decent speeds (IE I'd hope to reliably get 300+ kbps) and high data allowances of at least 100 MB per day at a price hopefully under 300b total. I will be arriving at the airport rather late (10 PM) and heading to my hotel which is in the Wat ratchabophit neighborhood. I hear that I should plan to go to a large mall to do the shopping for the card, so ideally, if someone who knows the area could tell me the name/location of the mall that would be convenient for me to do that.

Thanks!

Maybe best to get a SIM from DTAC/Happy as they operate 3G in metro-Bangkok on 850 Mhz. I use them and the service is fine.

You can get a SIM anywhere, for 49 baht. Then top-up (add money), then subscribe to a data plan.

You can get a one-week or one month plan.

http://www.happy.co.th/index.php?option=com_content&view=article&id=333&Itemid=368〈=en

Perhaps the 199 baht plan for one week might be ideal for you?

That looks perfect! I wonder why I couldn't find that plan. Thanks!