CNMI Guide

Drysuit diving in the Northern Mariana Islands

The Commonwealth of the Northern Mariana Islands (CNMI) is a group of islands that is a commonwealth of the United States. The island group enjoys a fairly stable tropical climate with little temperature variation throughout the year with the average being 27 degrees C. However, it is advisable only to visit during the dry season, which spans the period from the start of December to the start of June, as the wet monsoon season can be particularly dangerous, with tropical storms often wreaking havoc each year. These storms can include especially devastating typhoons therefore it is best, if possible, to visit during the spring months.      

With the calm and settled weather of the six month dry season it is possible to make the most of the diving experiences that the Northern Marianas have to offer. On a practical level, diving in the seas around these islands is similar to diving in any other tropical island location with clear seas and plenty of coral reefs to explore and enjoy. However, in many ways the Northern Marianas offer divers a very different environment, one that includes an abundance of sea life in marine sanctuaries, sea floors littered with archaeological remains and World War II wrecks and caverns and caves, such as Rota Hole, which create their own beautiful internal environments.


The three main islands of the Northern Marianas, Saipan, Tinian and Rota, each hold their own potential for particular diving experiences and adventures. The lagoon and coral reefs around Saipan are excellent spots for scuba diving as both are home to an array of tropical fish and other types of colourful and interesting marine life. But perhaps the two most impressive dives that can be undertake on Saipan are 'the Grotto' and 'Eagle Ray City'. The Grotto is a huge limestone cavern which is connected to the ocean by two underwater passages; this site was recently voted the second best for cavern diving in the world by the diving magazine Skin Diver. Eagle Ray City is equally spectacular, it is an underwater rock formation that is a prime spot for Eagle Rays; it is common for divers to hold on to the rocks whilst watching the Rays pass only inches above them. On Tinian, a twin coral offers fantastic photo and turtle spotting opportunities whilst the 'dump cove' contains wrecked World War II planes, tanks and ships that are always worth a look. Rota offers the Rota hole cave dive and is on the edge of a marine sanctuary.

To make the most of these deeper diving environments, especially the cave dives, you are going to want to spend significant amounts of time in the water. Even though these are relatively warm tropical seas, the best way to maintain stable body temperature and get the longest diving time possible is to dive in a drysuit. These specialist scuba diving suits keep the body dry and warm and are especially useful for long cave dives where many hours may be spent in the water. Drysuits are available from specialist diving suit suppliers like Wetsuit Outlet.