The Northern Mariana Islands are an archipelago made up by the summits of 15 volcanic mountains in the north-western Pacific Ocean.
Geographically, the Marianas are the northernmost islands of a larger island group called Micronesia. It consists of two groups, a northern group of ten volcanic main islands and a southern group. Only three of the islands, Saipan, Tinian and Rota, have a permanent population. Some of the islands that are unpopulated were evacuated as recently as 1990 due to the threat posed by volcanic activity.
The scuba diving around Saipan is excellent with the coral reefs and lagoon being home to a vast array of tropical fish. One of the best places for snorkelling is around Mañagaha, an old coral reef.
- Saipan - the Grotto, a huge limestone cavern and voted the number 2 cavern diving site in the world by Skin Diver Magazine.connected by underwater passages to the ocean.
- Saipan - Eagle Ray City is one of the most unique dives in Saipan. Rising out of the sand at a depth of 30 ft. is a rocky formation that on a good day will have up to 40 Eagle Rays swimming around it. The divers go down to the rocks and hold on as the Eagle Rays pass overhead. Many times the rays come within a few inches of the divers, making an opportune time for photographs.
- Tinian - Fleming - The best wall dive in the CNMI.
- Tinian - Twin Coral - a photographer’s dream... the name of the site comes from the two coral formations sitting next to each other. The site is also known as Turtle Point for obvious reasons. The fish life is fantastic with varieties of Parrot Fish, Grouper, Damsel Fish, and more. Great visibility.
- Tinian - Dump Cove - a wreck dive with many artifacts from WWII such as planes, tanks, ammunition, and jeeps. It is also a turtle feeding ground so the chances of running into a turtle are very high.
- Tinian Grotto - the most popular cavern in Tinian.
- Rota - Senhanom Cave (Rota Hole) -This is the dive site of many award winning underwater photographs; a grotto with schools of redfish, bronze sweepers and sometimes a lobster or two. The suns rays shining down through the roof opening can be most hypnotic.
- Rota - Sub Chaser, the scattered remains of a WWII Japanese auxiliary submarine chaser. One of three in the area. This site is within the boundaries of the marine sanctuary.