I'm starting to think the post office at Castaway Cay is a myth.

[Bishoparc]

It's been open on both of our cruises but I do have to agree with the afternoon recommendation. We got ours about 3 weeks after the cruise.

 

[PrincessShmoo]

If you note the name of the manager (on Olaf's left) it may clear a few things up:

 

[Jesslm80]

In September we got off the ship as soon as we were allowed to and the post office was open. Our post cards arrived 2 months later with a giant bite mark. Not kidding. Big chunk missing.

 

[Amanda129]

I've been lucky enough to mail postcards home on all 3 cruises I've been on. Delivery has ranged from 3 weeks to 2 months, but they've all managed to make it! If I remember correctly, I've always had the best luck first thing in the morning by getting off the ship as soon as possible. It's my understanding that having someone staff the office really depends on whether or not they can actually make it due to high surf or weather (I think the person(s) staffing the post office just use a small boat and can't/won't always make the trip from the main islands).