Surfside is a pretty pleasant place to spend an afternoon if you're hankering after some sun, surf and sand. It's the best, most swimmable beach in Oranjestad proper, with plenty of shade and a handful of excellent bars. Kids will love the inflatable water park just offshore, which offers swings, slides, monkey bars, climbing walls and a free-floating catapult.
It's only steps from the airport, so planes taking off and landing will give you something to look at (for better or for worse).
