Why doesn't my caller ID always show up on international calls?

Once a call crosses a border, your number stops being something we control. It passes through transit carriers and a terminating carrier in the destination country, and each of those can preserve, rewrite, or strip it to comply with local anti-fraud rules.

In Japan especially, carriers intercept calls with no displayed number, play "please call again with your number displayed", and hang up automatically. That is not PuchiDen rejecting the call — it is the destination network saying it can't trust where the call came from, and there is no switch in your account that forces it to work.

What actually helps: ask the person to temporarily turn off anonymous-call rejection (on DoCoMo, they dial 1480), or message them a heads-up before you call. Some numbers stay unreachable this way, and for those you'll need a different channel.

The full reason — what happens at each border and why the cryptographic fix doesn't yet cross national lines — is in our blog post: Why your number sometimes doesn't show up on an international call.