1950s/early 1960s, we nearly always had a U.K. seaside fortnight, somewhere in the SE or just once in Cornwall - always in a rented house, never a hotel. One or other granny and/or an aunt would often join us.
We had no car until I was 9 or 10, so until then we’d go by train, and oh, the excitement - who could be first to see the sea?
We always had a beach hut for all the paraphernalia of 4 kids.
I adored those holidays, and still love that seaweedy/seasidey smell, and the cry of gulls.
Much better off cousins of ours would go to Italy or at least Guernsey - very swanky at the time. To us, anyway!
I was 21 before I got on a plane, and that was to join dh (then bf) who was working in Cyprus. I’d been to France and Germany, but only for school exchange visits, by train/ferry/coach.