Recommended smoothest transition of an iPhone5?

I've got an unlocked iPhone5 I've been using here in the States with T-Mobile Unlimited.

I assume there's no real way to keep my US number AND use their services over there.

So what is the best temporary service I can use?  I've seen the vending machines filled with Sim cards.  What is the best to use that's easy to set up (requiring no second phone?) and I can use immediately when I'm there to call my family back home or coworkers in the UK, etc?

I figure I'd use a temporary until I can either upgrade it or get a real service over there.


Do you guys have any preferences for services with decent international plans?  SMS compatible, okay Data and texting (I don't use much at all as I'm not a phone person but I do need some functions for my international online banking).  I'm talking for after the temporary and into a real monthly service now.
I'd just like to be able to call places in the US without incurring the wrath of long distance charges. 


From what I understand I don't have to worry about compatibility issues with my iPhone5 too.  Is that right?

I don't know much of anything about the good service providers over there.  I used a temporary one once called like... Seven or some other number. 

Orange phone had a decent pray as you go plan with international long distance for something like 6p a minute about 5 years ago. They aren't Orange anymore,;they're EE now, but they may still have a similar plan.  I used them to call home a lot when I studied abroad in undergrad.

Do you guys have any preferences for services with decent international plans?  SMS compatible, okay Data and texting (I don't use much at all as I'm not a phone person but I do need some functions for my international online banking).  I'm talking for after the temporary and into a real monthly service now.
I'd just like to be able to call places in the US without incurring the wrath of long distance charges.   

I assume by temporary, you mean a PAYG (Pay As You Go).  Just to let you know, many people in the UK use this as their standard phone service, and don't ever sign up for a monthly service plan.  I used PAYG plans for about 2 years (but got a good deal on a SIM-only 12 month contract at that point).  There's no stigma here with using a PAYG phone like there might still be in the US, and what's offered in a PAYG is in many cases the same as what's offered in a longer-term contract.

I'm not sure what the best SIM card is for you.  You will want to check the services areas of where you will be located and how much coverage you get.  The main mobile networks here are EE, 3, vodafone, O2, and T-mobile, and all provide the same sort of things. You can easily compare PAYG and monthly plans at carphonewarehouse.com.  There's also giffgaff, which offers packages and runs off the O2 network.  Do a search on here, as I remember someone has a link in their signature bar which can get you £5 worth of free credit.

Plans can range from 500mb to 1gb data for £10/monthly topup-- which should be sufficient for your usage.  Instead of using an international plan to call the US for cheap, I typically log into skype or a free VOIP calling service such as Viber to make calls.  You will be able to download the apps for free.  Using viber, the person you're calling will also have to have viber installed on their phone for the call to be free (ie: use data only).  With skype you can call people in the US directly, though, rates will apply- unless the person you're calling is also logged into skype. With these services, there's minimal/no long-distance charge wrath incurred.

As you have an iPhone, you can also use voice only FaceTime to call other apple devices on wifi and 3G so that's another no long distance charge option. It's how my partner and I talk now between the US and UK.

It needs to be a micro sim card that starts off topped off.  I won't have a usable UK card to top the thing off for a few days.

Do a comparison search for PAYG SIM cards to find out what would be the best service for you and if you have to buy the SIM card online, or if you can go to a phone shop to buy it when you arrive. We used GiffGaff SIM cards in our unlocked iphones when we first arrived back in the UK and I had them mailed to the hotel where we stayed for the first few nights. I topped them up online and was good to go. I'm not sure how much GiffGaff charges to phone overseas as we use Skype and Facetime audio to call back to the US. I now have a contract, but only because TMobile (part of EE) had a deal where i pay 5 pounds a month for 300 mins, unlimited text and 1MB data.

Anyway you will find lots of choice here, lots of offers, and many different combinations of minutes, text and data. Remember that you will not be charged minutes for incoming calls so you may be content with fewer minutes than you have at present. For a start you could look at www.gocompare.com.