Works on unlocked mobile phones, in my case on my iPhone and my wife's Blackberry.

Many thanks everyone, for all the information and advice. It was a happy accident that when I bought my iphone (through Verizon), we ended up getting it when the phones were unlocked! Now I feel especially happy with my new toy!

I'll follow up with syncing the ipad with all the info so that we can access the data we need. That task will be saved for another day!

But hanuman, the number only lasts for 30 days if I understand A T % T correctly. My friends want to keep the same number each time they come to USa, which is frequently!

Carol,

My SIM, or US base phone number, fromT-Mobile only expired if I don't use it at all for 60 days and will be cancelled after 180 days of absolute no usage. Even after 60 days I can reinstate the SIM by calling T-Mobile if I wish or I could simply put it in my phone and use it briefly while I am abroad. If you're their so call "Gold" member your prepaid SIM will last 365 days.

It should be roughly the same for AT&T.

Re T-Mobile "Gold" members - the SIM will expired after 365 days of NO usage.

Hanuman, thanks for that information. Good to know. BUT, a T-mobile SIM doesn't have much calling area in the USA, at least not where we/they (Italian friends) live and travel in this country. Verizon is probably their best bet, but I have not found anything that isn't under contract.

Carol have you tried googling?

From a quick google search: http://www.verizonwireless.com/wcms/...aid-plans.html

There's a video embedded on the web page which clearly explains everything. There's also an online chat where you can ask about expiration etc.

All you do next is find the cheapest prepaid phone that uses the same type of SIM card as your Italian friend's phone and they can use the Verizon SIM in their unlocked phone.

Another simpler idea: If you're uncomfortable about giving up your US number (which is not an option for me), sign up before your trip for Verizon's Global Data plan - $25 for 100mg of data. Includes texts, emails, web surfing, Viber, Facetime, etc. I have used this recently on my iPhone for trips to India, Argentina, Chile and France.

Then, if you will also be making local and intl. phone calls, buy a cheap unlocked phone w/ a Thai SIM. (I use an old unlocked Blackberry). You end up with super cheap calls while using your own number for texting.

I thought I left this message yesterday but I don't see it today. We used the app for Viber which gives you free phone calls and text messages. I turned off the cellular data on my iphone and put it on airplane mode. No charges and the call I made on Viber to my granddaughter from Cambodia was crystal clear! The recipient has to have the Viber app also, though.

Thanks for the suggestions, crosscheck & pattyroth. I'll look into those. I think our needs are relatively simple so I'll probably just get the SIM card for our phones. Buying another phone is probably not necessary for us.

The Viber app sounds interesting and I'll check that out.

You really don't need a foreign SIM unless you plan to use your phone for local voice calling. We used our US phone to text our guides, just not to speak with them. If you get the data plan, you can text to set up times to talk by Viber/Skype/Facetime, etc.

Crosscheck, you make great suggestions. I'll look into that more carefully. There are some interesting options and we'll have to figure out what makes the most sense for us.

The Viber app is free.

crosscheck,
You make a good point about using text. Would texting be a preferred way to reach a guide or other person locally?

I don't imagine using the phone locally a lot but it would be valuable to have it for those once in a while times.

Thanks again, everyone.

<i>"Would texting be a preferred way to reach a guide or other person locally?</i> only if they read English!

Seriously though - a lot of people speak English but not very many can read or write English in Thailand.

Also, a local SIM with data plan will set you back around $10 - 15 for a month's usage so why not go for it. An iPhone with no phone capability is not very useful.

"a lot" = people in the tourism industry.

Another example from past experiences that happened to a lot of Fodorites - when you're in a taxi coming to meet me for a GTG and the taxi driver is lost - what are you going to do - text me? Good luck!

Hanuman,
Thanks for the reality check! You've convinced me (and I'm not missing our dinner, I promise!)

The SIM is in!

Paule