Before the First World War, things were still very formal, and as you can see, even a seaside holiday meant wearing hats, long dresses, and plenty of covering material if you went into the water!
Notice the tie Pinkie (Thomas) is wearing, and the formal sailor suit, including hat, of his friend. Coverage was the order of the day (but see on to 1926 for a very fetching bathing suit that still covered everything!)
Even the women in the photo below are wearing ties - this was informal wear, and as you can see, was for sitting on the sand! This photo was taken in Devon in 1911, and the picnic is actually taking place on the beach.
but it didn't make much difference where you were...here they are up in the hills...
And if you were a child in this period it didn't much matter what sex you were, you were still dressed up in outlandish gear for the formal photograph...