Can you take shells back on the cruise ship?
Yes, unless the cruise ship doesn't allow it. Dr. Jim
You'll be in a marine park and it is illegal to take anything with you.
Depends on where you collect them from. If from any beaches that are within Columbus Landfall National Park then it's prohibited.Edited: 04 April 2017, 08:33
Several main beaches on GT are part of the National Parks, so you're not allowed to remove shells. BUT, those same beaches are great for collecting sea glass.
Don't know what your cruise line allows though.
The entire length of the west side beach is national park. You can grab all the shells you want on the east side or in north creek.
With most visitors on cruise ships only in port for several hours; pretty well most of them buy their high quality finished shells in stores & are not taken from the underwater National Park areas. Dr. Jim.
Obviously, purchasing shells is fine. I would just point out that the National park extends to the beaches as well and not just underwater. I believe the boundary is a few feet beyond the high tide mark. Any shells taken from the beach would be illegal. Also, quite smelly.
I have read that Carnival won't let you bring them onboard, since they have no way of knowing where you got them.