The ones I got were individually bubble wrapped. Then I think they were put inside a ziplock bag. Can't remember if it was open or shut (seems like they would need air?) Maybe it was folded and taped. I really can't recall exactly.
Anyway, the two packages were then placed in the box with a thick layer of wadded newspaper above, below and around. As the other poster said, it was the bigger box, like cinder block size. She also marked the box as to the contents and warnings not to x-ray, etc.
No problems in transit, all eggs of one breed hatched though none of the other did. Most likely an incubation problem though.