Terminal 3 Departures has a post office! From the airport services page:
The post office is located on the 3rd floor, in the “Buy and Bye” Hall.
Days and hours of operation:
Sundays – Thursdays 07:00-22:00, with a daily break between 18:30 – 19:00
It doesn’t look like there are any postal services in Terminal 1. I can’t find any terminal maps for assistance, and while Google Maps identifies a location of Israel Post on the map there’s no way I can find it via pictures.
Last updated 24 December 2018