Will my iPhone (Australia ) work in Japan

I have a iphone 4 I use in Australia through Telstra, it has International Roaming built in BUT will I be able to phone Japanese mobile phone numbers whilst I'm in Japan and call Australia etc.?. I do not need data!...only use for voice calls to other mobiles in Japan and back home to Australia?. I've been told by Telstra that I can, but have a friend in Japan at the moment and he cannot use his phone, he only gets a message reading 'searching???". Confussed! Thank you.

What model number?

If it's a Telstra iphone 4 then it should be the GSM model (a1332), which should roam fine in Japan assuming you have the proper plans in place. Calling and receiving calls should work as normal. Remember that your phone works essentially as if it is still in Australia, i.e. you'll need to dial the Japanese prefix (+81) when calling Japanese numbers, etc.

Thanks for your reply, yes it is the GSM a1332 model. I would only dial the +81 number when making a call TO Japan...not whilst I'm in Japan!?...correct???...I've been told by Telstra that when I turn my phone on at arrival in Japan the phone will automatically connect to the Japanese network. Fingers crossed the phone will work as normal. My friend has a Samsung 'flip up phone ' with Telstra and has International roaming, he was able to use it ok in Hong Kong las week, BUT when he arrived in Japan it will not work?, Telstra Australia cannot explain this, only to suggest he turn the phone on and off to perhaps help it search for connection. Thank you.

International roaming

In general it can be costly.
If you are planning to do it, could be worth checking with your service provider. You would not like ending your holiday with a huge phone bill.

I would only dial the +81 number when making a call TO Japan...not whilst I'm in Japan!?...correct???

No, and that is a mistake that many people make. When roaming you have to use your phone as if it were physically located in Australia. Keep on using the +81 prefix or your calls won't go through.

...I've been told by Telstra that when I turn my phone on at arrival in Japan the phone will automatically connect to the Japanese network.

Yes, it should automatically connect to one of the Japanese Carriers (most likely Docomo of Softbank) and display their name instead of Telstra.

My friend has a Samsung 'flip up phone ' with Telstra and has International roaming, he was able to use it ok in Hong Kong las week, BUT when he arrived in Japan it will not work?, Telstra Australia cannot explain this, only to suggest he turn the phone on and off to perhaps help it search for connection.

Hard to say without knowing more details as Hong Kong and Japan use some differing technology, or an older phone could be the issue. But if the phone should work then turning it off and on again should help force it to reacquire a connection.

To 'yllwsmvf'...thank you... I would never have thought to use
+81 'in' Japan before calling another mobile number in Japan!...I had checked with Telstra Australia about using my phone in Japan which they said I could use BUT they did not tell me about firstly using the +81...thank you. I realise that the call cost are expensive to make and also to receive but for Emergencies It will be less expensive than hiring a phone. Many thanks!.

No worries. And as for costs, check your carrier roaming rates, but in many cases it works out better just to roam, especially if you only foresee making a few short calls/texts during your stay. Depending on where you're from, the roaming rates are actually pretty competitive these days.

On the other hand, I would prefer to rent if I was planning on receiving a lot of calls from Japanese numbers, as a courtesy to those calling me. Otherwise they would have to pay international rates to get in touch with me.

Emergencies are rare and special cases, so I usually don't factor that into my calculations.