Need to erase and reset iPhone to use Italy SIM card?

Hi, my comments in red....

Do I need to erase and reset my iPhone 5s to be able to use the unlocked phone?

No but to be on the safe side, a day or so before you leave do a Backup to your computer at home using ITunes. Do you need instructions?

Once it is unlocked, can I still use the phone as usual on my AT&T plan until I get to Italy and purchase the SIM card to use over there?

Yes

I don't want to have to reprogram the phone again in Europe since I will not be taking a Mac with me.

You should not have to.

It should indeed be easy:

Once you buy your SIM card, ask the clerk to insert it, set it up, and make a test call to be sure it's working properly. Turning on the phone, you'll be prompted to enter the SIM PIN, which you may be asked to enter every time you start up the phone. If text or voice prompts are in another language, ask the clerk whether they can be switched to English. Also find out how to check your credit balance (usually you'll key in a few digits and hit "Send").

Remember to record your new phone number so you can pass it on to friends and family.

Note that many countries require you to register the SIM card with your passport as an antiterrorism measure. If that's the case, it may take an hour or two after submitting the information before you can use the phone.

🙂

You shouldn't have to erase it to prep for unlocking.

Since the iPhone 5, the unlocking process has been simplified. I think the system unlocks on the activation server.

Take your computer with you (just in case)

But I recommend the 3/Tre Network while you're enjoying Italia.

This is how you do it .The process needs to be completed before you travel

How to unlock your iPhone for use with another carrier - Apple Support

Unlock your iPhone

First, your carrier will need to process your unlock request. Then you'll back up, erase, and restore your iPhone to unlock it.

So Apple have it wrong ?

The Apple instruction are dated June 2015 ,when do you think the Iphone 5 came out ?

No, I did... 😕

These are the latest I can find....

How to unlock your iPhone for use with another carrier - Apple Support

Correct

if you have now read the Apple guidance you will understand how

Once At&t have removed their lock that is it for life it is freed by them and is the same as buying an unlocked iPhone from Apple

I would follow the Apple instructions verbatim as they are as good as it gets. Since they are dated 6/11/15 they should be current. On a second reading... you would be backing up, erasing, AND restoring to unlock it once the carrier has confirmed back to you that your request has been processed. Other than time you should not loose anything.

Also, be sure to save your contacts' phone numbers in the phone itself, rather than on the SIM card; otherwise, you'll lose access to them when you switch SIMs. When storing phone numbers, include the + sign and the country code to ensure that your calls will go through, regardless of where you're calling from.

I was unclear on whether I have to do it again when I put my original SIM back into the phone upon returning home?

No....

elcpu wrote:

Also, be sure to save your contacts' phone numbers in the phone itself, rather than on the SIM card; otherwise, you'll lose access to them when you switch SIMs. When storing phone numbers, include the + sign and the country code to ensure that your calls will go through, regardless of where you're calling from.

iPhones do not store user data on Sim cards, nothing will be lost.

✅