Discover a Cave with Fluorescent Water in Ilha Grande

The Gruta do Acaiá is famous for the natural phenomenon of light meeting water, creating an impressive fluorescence.

In Angra dos Reis, you’ll find a true hidden treasure: Ilha Grande. And it’s in this region of paradise beaches that the famous Gruta do Acaiá is located. More than just a cave, it is an underground world of wonders and mysteries, housing one of nature’s most incredible manifestations you will ever see!

Exploring Gruta do Acaiá

Approximately 8 meters below sea level, there is a crack in the rocky coastline, through which the sea water accesses a subterranean hall that features a hidden stony beach.

The sunlight that enters Gruta do Acaiá propagates through the water, creating the phenomenon of fluorescence. When it’s completely dark, you can even see a turquoise green mist with twinkling and shining spots like diamonds. It’s an unforgettable scene!

The path to the cave

But to reach this submerged paradise, you must explore the region! It all begins around 10 AM when the guide will take you by boat to the starting point of the cave trail. Along the way, he will share stories and explain how the entire journey inside the cave will go.

The access is by land! The trail is easy to walk, with small ups and downs, some open areas, and sparse vegetation. Then, you will descend a staircase amid the rocks. From there, you’ll crawl through the crack for almost 10 meters until you reach the cave’s interior. Every effort is worth it, as the reward is incredible!

The cave is about 30 meters wide and has an average height of 1 meter. You’ll have plenty of time to admire the beauty of the place, swim a bit, and even snorkel! Oh, and the cave is dark, so don’t forget to bring a flashlight!