Which network does the SIM connect to? WAmazing April 09, 2020 01:45 Updated Follow The SIM card connects to the NTTdocomo network (4G), the largest network provider in Japan. Related articles When can I pick up the SIM card from distribution machine? How can I get a SIM card? List of airports where SIM can be took Can I make phone calls after inserting the SIM card? Can I change the time to collect the SIM card? Comments 0 comments Article is closed for comments.