Travel Technology - New iPhone SIM changes phone #, right?

So if I put an Italian SIM card in my iPhone while in Italy, that will give the phone a new number. Am I right about that?

So a caller will use that new number to reach me while I am in Italy.

What happens to calls made to my previous number, the one that has been in place for years & that I will return to using when I am back in the US?

Do they go to voicemail, can they be call-forwarded, do they vanish into the ether? If they go to voicemail, can I hear them?

Assuming your phone is unlocked so a new sim will work, yes you get a new #. The old sim with old number works when the old sim is put back.

I didnt check voicemail access or if they were saved.

Yes, new sim = new number. Calls made to old number will behave as if phone is off, generally that means straight to voicemail. You might be able to get into your voicemail by calling that number and hit # and then enter your voicemail pin if you have that set up.

Yes, new SIM from and Italian carrier will get you an local Italian number. Anyone can call that number from around the world, but it will be a long distance call for them. Calls to your current number will go to voicemail. You can most likely (depending on your carrier) dial your number from your italian cell and listen to them remotely, but that will cost you minutes.

Call forwarding is an option on many carriers (for example on Verizon you dial *72 and then the number you want to forward to) but most will not allow forwarding to a foreign number - too costly. There are some services out there that will issue you a US number that you use for forwarding and then they will forward overseas to your new Italian number for a small fee. Just google "international call forwarding" and you will find a number of them. PM me if you want and I can tell you who I used, it was pretty easy.

One neat way to receive calls placed to your old SIM is to purchase a Skype phone number. That will cost you $18 for three months; there are lots of area codes / exchanges to choose from. Then tell you need to setup two call forwards JUST BEFORE you leave the country:


Forward your old phone number to your new Skype number (no charge to your callers)
Forward your Skype number to your new SIM number ($0.31 / minute to your Italian mobile phone).
Don't forget to disable both forwards when you return and install the old SIM. Otherwise you'll incur charges and wonder why you're not getting any calls!

On the downside:

I have found that there is some quality degradation in this "double forwarding" technique.
I'd guess others on the forum have discovered cheaper ways to accomplish this.
People calling your old SIM probably think you're in their time zone...

I prefer Google Voice because: (a) it is free; (b) you can text to/from it; (c) Talkatone (free) has works well over 3g; and (d) it has free visual voicemail with transcriptions. Its downside is that it requires a little bit of hacking to get it to call forward to an international number. You need either sipsorcery, freepbx, or soemthing similar.

Assuming your phone is unlocked so a new sim will work, yes you get a new #. The old sim with old number works when the old sim is put back.

I didnt check voicemail access or if they were saved.

For Vz iPhone 4s, any voicemails on Vz are saved and they should be 'activated' if you use your Vz rather than overseas sim number. For instance, when I touch down upon return home, I check my voicemails on Vz without any issues.

Great responses. confirms what I expected, but never having done this, I wanted to be sure.

My first trip to this forum & I'm impressed.

Thomas S. England

Photo Portfolio: http://www.EnglandPhoto.com/portfolio/

Images of Italy: http://www.EnglandPhoto.com/Italy/

Thanks for all the detailed responses. This is just what I suspected, but never having gone this route, I wanted to confirm.

BTW, this is my first encounter with this forum & I must say that I am impressed.

Thomas S. England

Photo Portfolio: http://www.EnglandPhoto.com/portfolio/

Images of Italy: http://www.EnglandPhoto.com/Italy/

So if I put an Italian SIM card in my iPhone while in Italy, that will give the phone a new number. Am I right about that?

So a caller will use that new number to reach me while I am in Italy.

What happens to calls made to my previous number, the one that has been in place for years & that I will return to using when I am back in the US?

Do they go to voicemail, can they be call-forwarded, do they vanish into the ether? If they go to voicemail, can I hear them?

If you don't forward your calls any calls to your regular number will go to voicemail.

Assuming you have the retrieval code for your voicemail all you would have to do is call your number and simply enter the passcode.

I prefer Google Voice because: (a) it is free; (b) you can text to/from it; (c) Talkatone (free) has works well over 3g; and (d) it has free visual voicemail with transcriptions. Its downside is that it requires a little bit of hacking to get it to call forward to an international number. You need either sipsorcery, freepbx, or soemthing similar.

Those PBX'es do make things complicated; perhaps easier would be to forward to a Localphone Incoming Number (or VoIP.ms DID, etc.) which can then be forwarded to the international number really cheaply? Better than Skype, at least.

I love my Asterisks box. It took a little work to get it going, but there is just so much I can do. I have unlimited VOIP extensions, use IAX/2 which is not blocked anywhere near as much as SIP, I have call directors in multiple countries, and more. I have my own least call routing and have rates that are wonderful because of it.