Japan Phone GuideMobile phones in Japan, made simple.
SIM

SIM lock

A restriction that ties a phone to one carrier. New phones sold in Japan are now generally sold without it, but older devices may still be locked.

Dictionary

Related guides

Activation / kaitsūkaitsū
The step that switches your line onto the new SIM and network. Until activation finishes, the new SIM has no service.
eSIMī-shimu
A SIM built into the phone that you activate by scanning a code or through an app — nothing physical is shipped.
SIM cardshimu kādo
The small chip that connects your phone to a mobile network. Comes in a physical form you insert.
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