This past weekend we discovered this awesome skate park in Poble Nou. It's right by the beach and only a few blocks from the Poble Nou metro stop. Mar Bella is down the beach from the crowded touristy Barceloneta, which makes it even better! This is a great skate park for kids with skateboards or scooters, but plenty of adults were showing off their skills as well. I also loved that there was a grassy park right next to it with some shade.
I suggest packing a lunch or stopping by a market to grab some snacks and water before you get there!