Haneda Clearing Immigration

Hi guys,
Ive only flown in to Haneda once previously and I cannot remember, so sorry for the question.
I will land at 3pm at the international terminal.
I will need to get the shuttle to terminal 1 for the post office to pick up sim cards once having cleared immigration and pickied up luggage.
The post office closes at 5pm.
From what I think I remember, I should be able to do this without an issue (as long as I am not delayed)... but I am not sure...
2 hours from touchdown to closure, should be ok, right? :)

thanks in advance.

That should be sufficient time, with plenty to spare. Since you've been to the International Terminal before, you should be okay with directions.

From my experience, the immigration/customs line at Haneda moves much slower than at Narita. I'm sure it depends on the time of day, etc. You may be cutting it very close.