Well, if it is Man from Atlantis, I can check for I have that series, I think (at least the movies), in the library.
The thing is, I don't recall the women in mini skirts. Ie,
space1970: Diving Into The MAN FROM ATLANTIS (1977)
(that's Jean Marie Hon, of Ark II fame, in the background.
I was first thinking it was UFO with some confusion since SkyDiver women wore slacks.
Is it possible that it might have been "Primus"?
https://www.imdb.com/title/tt0124250/?ref_=fn_al_tt_1
Or, perhaps, "City Beneath the Sea"?
https://www.imdb.com/title/tt0065556...1?ref_=nv_sr_1
Neither one hits it dead center but with a young Eva Renzi in Primus, it is possible......and while "City" was a movie and not a TV series, it was known for mini skirts!