The Grotto

Saipan Grotto - Blue Grotto of Saipan

Useful Information

Location: Follow As Matuis Dr, turn off at Grotto Dr.
Open: No restrictions.
Fee: free.
Classification: SpeleologyKarst Cave
Light: n/a
Guided tours:
Address: The Grotto, Grotto Dr, Saipan island, Northern Mariana Islands
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
Please check rates and details directly with the companies in question if you need more recent info.



The Grotto is also called Blue Grotto of Saipan, a collapsed karst cave filled with sea water. The sun shining into the water filles the cave with a strange blue light. The road leading to the grotto ends at a parking lot with a solar powered emergency phone. From here a trail leads down 109 steps to the ground of a huge collapse doline with sea water at the far end. Standing at the water the blue light indicates the cave opening to the sea at the other side of the underwater cave. Diver see that the pool is a bout 18 m deep and actually has three openings to the sea.

The Grotto is a famed diving spot and very popular. On the other side cave diving is rather dangerous, even under such relaxed conditions in this tropical paradise. There are regularly diving accidents in the grotto, typically people who get panicked in the cave and try to reach the surface. It is actually rather easy to reach the surface, as the cave is not that big, but to emerge without proper decompression causes embolisms.

Entry and exit for the divers and snorklers is a rock in the middle of the collapse. Visibility is around 30 m, one of the best Saipan has to offer. The cave is full of sea live, including harmless white-tip reef sharks, barracuda, and pyramid butterfly fish. Sometimes green sea turtles, Napoleon wrasses, tuna, and spotted eagle rays can be seen. Do not leave the cave to the sea, because reentry is difficult due to currents and there is no exit point for divers outside the cave.