I arrive tomorrow morning but it's cheaper to get the week pass for the duration of my trip.
I have bought the pass before midnight Thursday, if I activate it tomorrow at the station; I assume it'll be valid until Sunday this week?
When buying, it did say for this current week. No where on the website does it mention when it needs to be activated by
Navigo week passes are active depending when they are purchased, not by first usage at a fare gate / turnstile / barrier.
If you purchased a Navigo Week Pass before Thursday midnight, it is active immediately until Sunday midnight.
A Navigo Week pass purchased after midnight Thursday, is active after Sunday midnight (i.e. Monday).