For a fun park that looks out onto the Port River head to Joyce Snadden Reserve, just a short walk from the big Port Adelaide attractions. There is lots to do at this park, and some nice views to look at while you're doing them. This park is best to visit when you've got the kids, so that they can enjoy the attached playground.
There is a large grassed area at the park, this is a great area for playing ball games. There is lots of room for kids to run around, and you could easily set up a game of soccer or footy. Just be careful that you don't kick the ball too hard, or it could end up in the river. The park is also a nice area for flying kites or having a throw of the frisbee.
Unfortunately the grass at the park isn't in a great condition, so it isn't a particularly nice spot to picnic on the ground, but if you brought a picnic blanket along it wouldn't be too bad. There are no picnic tables at the park, but there are benches if you'd prefer that. The park does feature a barbecue, so if you're after a cooked meal you'll be able to enjoy one for lunch here. If you're looking for a place with nicer grass to enjoy your meal, you could always head across to Old Canal Park just across the road.
There is a reasonably sized playground at the park, that would be fun for the kids. Here you'll find all of the usual playground equipment, plus some added extras. There are fun swings, climbing frames, monkey bars, a bridge to cross, and a flying fox. Kids will also be able to have fun riding their bikes along the path that goes around the park, if you follow the path you'll also be able to find a riverfront bike trail to continue on.
Joyce Snadden Reserve isn't exactly the prettiest park around, but it has some good facilities that make it a good place to visit with the kids. The great views of the Port River make up for the fact that the grass here isn't quite up to scratch. There are picnic facilities and a playground for the kids.