Hōlei sea arch, Natural arch at Kau coast, Hawaii, United States.

Hōlei sea arch is a stone formation that extends from steep basalt cliffs into the Pacific Ocean at the end of Chain of Craters Road. The volcanic rock rises roughly 90 feet (27 meters) high, creating an open gateway above the water.

This formation emerged through uneven erosion of an ancient lava flow that solidified roughly 550 years ago in this region. Different erosion rates on the rock gradually carved out the arch shape over centuries.

The name Hōlei comes from Hōlei Pali, the cliff of the volcano's slope above the coast; hōlei is also a native Hawaiian shrub of the milkweed family that grows on the surrounding lava. The arch stood at the end of Chain of Craters Road, where the road is buried by lava from Puʻu ʻŌʻō's eruptions since 1983.

The best view of this formation is from an observation area near Chain of Craters Road, where parking and restroom facilities are available. Weather can change quickly here, so come prepared for rain and strong winds.

The arch stood until late September 2026, when it fell into the ocean around the time Hurricane Nolo passed Hawaiʻi Island. The park confirmed the collapse on October 1, 2026, after reports spread on social media once the park reopened; the exact time is unknown, only that it was gone by the night of September 27.