It would be. But these would probably be ceremonial uniforms and their actual sea gear would be futuristic stuff. For sure it would outclass
Voyage to the Bottom of the Sea, even if the inverse would be the same crew exploring outer space.
Mr Spock would also probably be better off different than that. He would have some traits of a sea creature, at least partially. For example the early concept art for Han Solo. He was described to be conceptualized as a green alien with gills. It would be much closer if not the same as my concept for a sea Spock: