Matthew Vandamm

I'll be visiting Seattle/Portland/LA/San Diego for three weeks in September/October and was wondering if you experts could assist.

Is it possible to load a prepaid SIM into an iPhone 3GS (O2, but can get unlocked) without syncing with iTunes?

I was kind of hoping to get away without taking a laptop with me (surviving with iPhone only) and wondered if anybody had experience with this.

Jay K

Your wireless will still work in airplane mode. We did this with our iPhones in Japan. The only rub is finding free wi-fi.

joejones

iOS now has the option to deactivate 3G roaming while leaving all the other radios on. This is much better than airplane mode -- you can get incoming calls and SMS on your regular number, and also use the GPS (assuming you have a pre-loaded map or wifi access).

I have tried messing with prepaid SIMs before, but now I find it easier to deactivate 3G roaming and survive on wi-fi. My wife and I traveled around Europe this spring and to Saipan this summer, and we were often able to get wi-fi in our hotel, in cafes/restaurants, or just walking down the street past someone's apartment.

If you have some sort of VOIP software on your phone (e.g. Skype), you can call people back using cheaper VOIP at a wi-fi spot. You will pay through the nose to talk to people using your regular SIM, but it is still free to receive a call without actually answering it. Just note the number, find wi-fi and call or email back.

pdxer

you will need to unlock it to use an at&t sim. t-mobile will also work but on 2g only and they don't have data on prepaid anyway.

once it's unlocked, it should work when you swap the sim. it would probably be a good idea if try with a non-o2 sim before you leave to see if there are any surprises, but i don't think there will be.

potfish

As said above you need to get O2 to unlock it. Once that's done, put a non-O2 SIM in it and it might ask you to sync with iTunes again, but then after that you should be able to swap SIMs around without further need to sync. Like a normal phone!

If you do use your O2 SIM abroad, beware the iPhone data roaming bug - even with Data Roaming switched off you can still consume data while roaming. There are many cases on the web, and I have had this personally too, but nobody seems in a hurry to fix it. I might be wrong but it seems that if you start downloading something on wifi and lose the network, it'll finish the download using the cellular network. I argued the charge with O2 and they refunded it (it was only a few quid), but the only sure way to avoid data roaming charges if you do roam is to deliberately corrupt the APN in the Mobile Data Settings.

weekilter

Other consideration is you will only be able to use it on T-Mobile if you have a SIM cutter to convert from standard SIM to micro SIM. The only way you could use it on T-Mobile (EDGE speed only) is to sign up for the "flexpay" service and choose a data package. Regular prepaid does not have any usable data.

If you intend on using AT&T their regular prepaid service will not work for the iPhone. I'm not sure what AT&T's policy is for service whether if you don't have a credit file whether you can even get service from AT&T for a short time or whether they require a year or multi-year commitment.