Cellphones in Japan

Hi,
I'm an American who will be in Japan for 6 months. I have an I phone 4 that I use here in America with AT&T. What is the best way to use a cell phone in Japan for my 6 month stay? I want to be able to use LINE on my phone so I guess I'm going to need a smartphone.
I know AT&T has an international plan but it is too expensive.

Any other ideas?

I have an I phone 4 that I use here in America with AT&T. What is the best way to use a cell phone in Japan for my 6 month stay?

Get it unlocked and then use it with a Japanese carrier. B-mobile or econnect are often recommended for data.

^ agreed. if you look you can find a reputable dealer on eBay that will cost almost nothing to unlock your iPhone 4.

What part of Japan are you visiting?

Or do a carrier unlock via ATT. I believe its a free service provided you meet the requirements.

https://www.att.com/deviceunlock/?#/

Thank you for your responses.

I will get it unlocked and get a prepaid sim for data only. I guess I cant use voice phone calls so I will be using mostly apps like line.

B mobile has a visitor sim of 1 GB for 3,686 yen but only lasts for 14 days.

E connect has 1 GB for only 4,100 yen and lasts for 30 days.

Does anyone have any experiences using e connect? Is the speed fast enough to use?

Thank you.

I'd recommend so-net.

It's an LTE SIM, but works in a 3G phone.

http://www.so-net.ne.jp/prepaid/en/

You can get 3G initial that lasts 60 days, around 5000 yen. Then you can top up at 1G for 2800yen.

You can find these in Yodobashi Camera

If you used that phone on att for 2 years they will unlock it for free.

If you couldn't get your iphone unlocked;

You can't buy phone in japan if you don't have an address and usual identifications. You can rent a mobile at Narita airport for free and only pay for the data you use.

why not get a 5GB x 6 months prepaid data only SIM from BMobile?
http://www.bmobile.ne.jp/5gb6m/plan.html
http://goo.gl/Nq0WWX
It cost 18,+++ yen, so roughly 3,+++ yen per month.
You'll get 5GB/month and speed down to 200kbps once you over the monthly limit.

You can use your iphone 4 (unlock) with he SIM, and run LINE apps.