What is eSIM? Easy Guide for Using eSIMs in Japan If you are touring Japan or making plans to live there for a short time, staying connected is critical. Traditionally, vacationers used physical SIM cards to get cellular service and calls. But now, there's a newer, smarter option known as eSIM . In this manual, we'll give an explanation of what eSIM is , how it works, and how you could use it...