Mermaid Cave / Tunnels

Mermaid Cave / Tunnels
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Address 416 Keaulana Ave, Waianae, HI 96792
Potentially dangerous but beautiful water cave near Nanakuli Beach Park.

• General: Cost: Free • General: Photo Opportunity • Hiking: Level: Difficult • Hiking: Rock Climbing

Mermaid Cave, or tunnels as it's often called, has grown in popularity in recent times. But this is strictly for the adventurous few seeking to experience a hidden treasure in Hawaii. Mermaid Cave is located at Nanakuli Beach Park / Nanakuli Community Park / Kalaniana'ole Beach Park. To get there, you'll cross jagged lava rock that could cut up your feet, descend through an open hole (or puka) below into a breathtaking underwater cave.

However, just like any activity in Hawaii, you need to be careful. Exploring any cave, especially a wet cave, is incredibly dangerous and not for most people to attempt. The water level in the cave will change with the tides but can also fill suddenly with any large swell.

If you decide to enter the cave, something we do not recommend, then it should only be done during low tide and calm water. The cave fills and drains with the surge of the tide. Do NOT attempt this in a surging swell. When you're ready to get out, you'll need to be able to lift your own bodyweight to get out through the puka. Some people require help and pulled up by friends, just one more reason to seek adventures and do your exploring with friends.

Mermaid Cave is an adventure. It's beautiful, relatively hidden, and potentially lethal if you're not careful. Check it out from the outside instead or try one of the many other Oahu activities that are less dangerous.