From volleyball.org:
Early 1920s
Most accounts place the sport’s origin in Santa Monica, California,
where the first Volleyball courts were put up on the beach
at the Playground (Santa Monica).
Families played 6 vs. 6.
Go back about two millenia to the Villa Romana del Casale in Sicily, where a 4th century A.D. mosaic depicts young women in strapless tops & briefs performing a variety of athletic feats. Truly there is nothing new under the sun.
If it’s a matter of either bikinis or burqinis on the beach, the choice is obvious for civilized people who value personal freedom.
Right - for 6x6, yeah it did get started in SoCal and was pretty much the same game that was being played indoors.
The evolution of that game to the 2 person beach game is what is frequently debated and as I mentioned, SoCal, Australia, and Brazil all argue that it became a thing in their areas first.