Punalu'u Beach Park is the most famous black sand beach on the Big Island of the U.S. state of Hawaii. The beach’s black sand is made of basalt and created by lava flowing into the ocean which explodes as it reaches the ocean and cools. Punaluʻu is frequented by endangered Hawksbill and Green turtles, which can often be seen basking on the black sand. This is a perfect place to enjoy the scenery, explore the black sand beach, watch the sea turtles, and swim or snorkel. Swimming is dangerous as the area is very rocky. Instead, you can also spread out a blanket under a towering coconut tree for a midday picnic or afternoon siesta, or sit for hours watching the action in the park's beautiful freshwater fish pond.

The beach has a large amount of underground fresh water that flows in it. This fresh water is very cold and looks almost like gasoline mixing with the water. Legend has it that in the time of drought, the ancient Hawaiians living in the area would dive underwater with a jug to get their fresh water.

Punalu'u Beach Park is located off Hwy 11 on Puna district's south shore, south of the town of Hilo.