There is a postal shop in Terminal 1, Floor U1 in the Service Center. From the interactive terminal maps, it appears it’s near some local transport ticket machines and the escalators to floor E0.
The hours are weird because of the pandemic: open 9am-5pm local on Monday, Thursday, Friday, and Sunday. Apparently it’s closed the rest of the time.
Terminal 2 and Terminal 5 are both currently closed, so those aren’t listed here.
I have to imagine there may be a postbox or six in the terminal somewhere, but I gave up looking after ten minutes with the interactive map. I imagine I’ll be updating this once T2 and T5 come back online, or when the malaise relents.
Last Updated 22 November 2021