UK iphone 4S in Japan
 

Apologies if this duplicates information elsewhere but I cannot find an exact answer via the search tools or my mobile phone provider's website.

I have an unlocked UK iphone 4s 32GB. Bought from Apple, currently has my O2 pay monthly SIM installed.

Will this work in Japan?

I last visited Japan in 2009 with my old iphone 3S which refused to work at all.
Would prefer this not to be the case when I go this week!

Thanks in advance

I don't know about unlocked UK phones with someone else's SIM, but my regular US iPhone 4 did work in Japan, although at sky-high roaming rates. You may be able to rent a Japanese iPhone SIM, but foreigners without residence visas are not allowed to actually buy phones or SIMs.

I know, regrettable policy instituted about eight or ten years ago.

Thanks - I'm not planning to make a lot of calls.

Probably will leave it switched off most of the time and switch on to pick up urgent messages from time to time.

I will try to get an iPhone SIM though - thanks for the tip.

Yes it will work. NTTdocomo and Softbank both operate on UMTS2100, same as UK.

You can buy a data SIM as described in the data SIM thread. With a data SIM you can still make phone calls with VOIP apps like Skype. Be mindful of Japan's vastly different manners regarding mobile phone usage though.

beware that the 300kbps data SIM card does not support VoIP. You have to get the high speed one.

The 1 GB card would work too. Probably better than the bitrate cards. From what I have read about the bitrate cards, they have many restrictions and filtering in place to keep you from using streaming services.

I have used both and can confirm that the 1GB card works with VoIP including Skype.

VoIP(among other things) is specifically forbidden on the 300kbps card.

If it's Internet access you want, that works fine on wi-fi, which is becoming more common in the cheaper hotels but not in the expensive ones. Since I stay exclusively in cheap hotels, I don't bother with a data card.

Thank you all for the advice.

I think I will try to rent a pocket wifi device from these guys

http://www.globaladvancedcomm.com/pocketwifi.html

If I do I will report back on how it works

Thanks again

Update
 

I should have mentioned - we are going on a wildlife photo trip that will involve the monkey park at Jigokudany then on to Hokkaido, staying in Rausu, Lake Kussharo and Tsurui.

The hotels we will stay at have no internet access, according to the tour organisers.

Looks like there is no wifi coverage with the device I mentioned above in those areas, so I probably will not rent one.

bmobile/NTT docomo coverage map in Hokkaido.
http://www.nttdocomo.co.jp/support/area/hokkaido/foma/