Stop to marvel at periodic bursts of foamy ocean spray from the Halona Blowhole, between Hanauma Bay and Sandy Beach. Formed by lava tubes at a time when volcanoes were still active on Oahu (thousands of years ago), the tubes extend into the ocean. When the surf is just right, seawater shoots nearly 30 feet into the air.
- The blowhole is most active when the tide is high.
- During whale season, this is a good place to spot them.
- Heed warning signs; there have been serious accidents and fatalities here.