Karajini National Park located a few hours south of Port Hedland. This is by far one of the most beautiful places I've ever been. We spent our time hiking and swimming around Dales Gorge.
We started with a hike from the car lot to the Fortescue Falls. It's a short walk down some uneven steps on the cliff. At the bottom are the falls, and a nice swimming area. This pool is fairly shallow compared to the others.
On the opposite side of the falls is the opening to the Circular Pool trail, a nice 3km return hike. It takes you to each end of the gorge. If you enjoy climbing around on rocks and water it's a great trail.
After a nice swim, it's time to turn around and go back to the falls entrance. Once you've gotten back you might want to go for a swim again. There's another great pool behind the falls one, walk up the rocks, but don't head back to the car park yet. Look for the trail in the trees which will take you to Fern Pool. While walking look up in the trees and you'll see tons of sleeping fruit bats.
You'll reach a patio, and there is what was my favorite of the three pools. If you dangle your feet off the deck, the fish will nibble your toes and give you a little pedicure.