One of the main reason we go to Oostende is so that the kids, and us, can ride the cars and bicycles they have available for rent on the boardwalk.
A lot of places offer them, and the variety of vehicles is pretty large. You can rent electric or pedal cars for the very young, starting even at 2-3 years old, and for bigger kids and grownups you can rent these quad-cycles for two, three, to up to ten people.
Renting them is not expensive and it's a lot of fun for everybody. It's a great way of seeing the entire boardwalk which is pretty long. Renting is done by half an hour or an hour and you keep it as long as you wish with paying at the end. The longer you rent it, the cheaper it is.
A form of ID must be presented and kept as warranty while you ride your chosen vehicle.