Hello. I'm new here, so sorry for jumping right in without intro. I wonder if any of you could give some advice on how to get about using a cell phone in Japan (Tokyo in particular).

BTW, dear son and I are Zed-ing to Tokyo from SFO on NW in mid-May. So far the reservation site shows wide open available seats (over 100). How quick do the seats get sold around this time of the year? Anyone know? Thanks in advance.