If you find yourself arriving to Tokyo – maybe via the Haneda airport – and having bought a Japanese prepaid SIM card – Pocket SIM – at the airport which you cannot get working, maybe this will help.

The included pamplet says to use the following settings (so maybe Google led you here?)

Name	ppsim
APN	ppsim.jp
User name	pp@sim
Password	jpn
Authentication type	PAP or CHAP

but they won’t work.

The actual settings can be found in this Twitter thread. Try the following (Pocket SIM Premium)

APN	ppsim.jp
User name	pp@psim
Password	jpn

or (Pocket SIM)

APN	psim.jp
User name	japan@psim
PAssword	japan

or

APN	dm.jplat.net
Username	pocket@sim
Password	japan

P.S. If you haven’t bought the SIM card already, I recommend that you try to find the U-Mobile prepaid SIM card, which is sometimes sold in vending machines.