1. The Mediterranean beaches — The whole coast
Free, everywhere, and the thing children will actually remember.
Israel has around 190km of Mediterranean coast and the beaches are free, well maintained and lifeguarded through the season, with playgrounds, showers and cafes at the main ones.
Tel Aviv's are the busiest and best equipped, with a 14km promenade good for cycling and scooters. Netanya, Herzliya, Haifa and the northern beaches around Akko and Nahariya are quieter.
Lifeguards operate posted hours and the flag system is taken seriously — swim between the flags and while the lifeguard station is staffed, because the Mediterranean here has real currents.
Good to know: Swim only when the lifeguard station is staffed and between the flags. The currents are not decorative.