Mermaid Caves

Make your way across lava rocks (sturdy shoes are a must!) and through an open hole to reach the Mermaid Caves, a secret beach and underwater cave. These unique half-submerged caves are only accessible during low tide, and you'll need some upper body strength to pull yourself back out—or you can always bring a small ladder. Visiting will children is not recommended. While the caves can be accessed during high tide, this is ill-advised as it requires you to snorkel around the beach and past sharp, dangerous rocks. Visit the caves and other off-the-beaten-track gems in Hawaii, like Ka'ena Point State Park and Ko Olina Lagoons, on a private guided tour. – Tripadvisor