Ocean water is not be entered by humans. Unseen things that can eat you live there; like great whites.
The movie Jaws was all the education I needed.
It’s the surface that’s the dangerous spot. You’re at the boundry of two worlds. I thing I’ve noticed during my few dives (I’ve only done my certification dives) and been told also by veteran divers is that once you are under the water most of the critters really don’t care about you since you’re pretty much part of their world. It’s when you’re on the surface that you’re seen as prey (since animals like sharks like to ambush from beneath).