Is there any phone planning I need to do?

Yes.  There are quite a few options for cell phone use in Japan, but for best results, you need to find some things out or arrange some things before you leave.

Contact your phone service provider.  Find out:

  1. Whether they offer a reasonably-priced international plan, especially for Japan.
  2. Whether your phone is SIM-locked (can install another company’s SIM card).

If your phone is SIM-locked, your best option is to arrange an international plan with your current phone provider before you go to Japan.

See also How Do I Contact My Family and Friends?