Sea urchin

so when I dove yesterday I grabbed 3 sea urchin for a friend. but I dont know how to store them until I can get them to him. any advise?

They don't last too long in my experience. A day or two is probably the most you want to wait before eating them. Tell your friend to hustle.

a cooler full of salt water and kept cool should do it for 2 days, or so I've been told.
I've transported them back to sac a few times and they are good the next day if on ice.  but by day 3 they were funky

I just keep them cold. Either in the fridge or in a cooler with hard plastic re-usable ice packs. I make sure they don't get any fresh water on them. They have lasted 2 days like that for me.

Or you can just clean them for him and refrigerate while they are still alive.

I just cleaned a bunch and froze the roe for 2 days. made uni last night they were still good, a little soft but fresh.

When I buy fresh sea urchin in LA, they remove the "meat" and store them in saltwater. They have them in the fridge for up to week and can be placed in the freezer too.