Where is the post office at Schiphol airport? /

Post office:
You can buy envelopes and postal stamps in the shop 'Service Point Schiphol Plaza'.

Find 'Service Point Schiphol Plaza' on the map here.
Service Point is located at the arrivals level, between arrivals 3 and 4, next to the shop 'Rituals'.
Open 7.00-22.00 daily.

Mail Drops (orange postal boxes):