The Blue Hole is located in the northeast corner of Saipan. It is a natural cave connected to the Pacific Ocean and a cave diving site. The sea water shimmers like a cat's eye blue, and the breathtaking electric blue sea water and the natural stalactite scenery are beautiful. Internal and external environment The blue hole looks like a dolphin with an open mouth, and inside is a huge stalactite cave. There are two natural swimming pools in the blue hole, which are connected to the outer ocean through an undersea channel, and light penetrates into the hole through the water channel from the outer sea , The blue hole pool can reveal a light blue luster, which is quite beautiful. This penetrating electric blue is also the origin of the name of the blue hole. For those experienced deep-sea divers, it will be an unparalleled experience, so it is known as the second largest cave diving destination in the world, after the Blue Hole in Belize. Diving conditions The depth of the Blue Hole can reach up to 47 meters, so only those with an AOW diving certificate can dive deep. However, those who do not have a certificate can conduct experiential snorkeling under the guidance of an instructor. Most of the people diving here are Japanese, and there are some Europeans. Generally, tourists come here for a simple snorkeling except for a look. Because there is no diving license, very few tourists come to deep dive here. If you have a diving license, you can enter the blue hole through the LetsdiveGuam diving club. In addition, there are more than 100 steps paved with small stones to go down from the top to the blue hole. The steps are somewhat notched, steep, and very slippery. When you get to the bottom, you will see a blue sea in the cave pouring into it. Due to the influence of the tide, sometimes the level in the cave is still without waves, and sometimes it is undulating, so you must be very careful whether you are swimming or diving in the cave.