I was talking about the US. The women dress tzniusly so it wouldn’t be a problem if men showed up. I had thought Frum men also go to the beach during off-seasons or at night, but maybe I was wrong about that. The only time I remember going was for Tashlich on Erev Yom Kippur. I went with a family including the husband, and I think there were only Frum people there.
Probably, goyim wouldn’t go to the beach when there is no lifeguard, so maybe that’s how Frum people are able to go.