All suited up

When we were in the Outer Banks last summer I spotted lots of swim shirts.  Not just on kids either.  Adults were wearing them left and right too.  Gigi picked one up while we were there and LOVED it.  Most of them are mock turtlenecks with long sleeves.  They seem like they’d be hot but she swore it was nice and cool.  As a planner AND the whitest girl you’ve ever met, I’m very interested in procuring one of these for myself and CSP.  Kidlet will be outfitted as well with a full on swim outfit.  Anyone out there (adults) have any experience with these?  What did/do you think?  What if you have the boobs?  Do they come with bras in them?  Do you wear your own bra thing under it?