Saudi Arabia has embarked on a race to explore unseen parts of the Red Sea, aiming to safeguard and preserve the Kingdom’s biodiversity under Saudi Vision 2030. The Red Sea Decade Expedition — a mission that endeavored to comprehensively explore the Red Sea — has already yielded a long list of discoveries. The discovery of blue holes in Saudi Arabian waters was among the most remarkable. At about 40 nautical miles off the coast of Al-Qunfudhah, the blue holes can be viewed from the sky as perfectly circular coral reefs that encase a distinct blue color, marking deep water inside. We sailed toward the southern Red Sea aboard OceanXplorer — a research vessel equipped with manned submersibles, deep-sea robots, a helicopter, and other advanced technologies. We were aware that the Farasan Bank — a submerged carbonate platform boasting the world’s third-largest coral reef system — held extraordinary structural complexity beneath the sea’s surface, but what we found exceeded our expectations. We reviewed nautical charts of the Farasan Bank, and an area of seemingly deep water between a labyrinth of extremely shallow coral reefs caught our attention. These areas had not been mapped in more than a century, nor had they been subject to targeted scientific exploration. Blue holes’ discovery solidifies Saudi Arabia’s status as a world-class ecotourism destination and global leader in marine conservation. Shannon Klein Using OceanXplorer’s helicopter, we surveyed the sea’s surface and found 10 of the blue holes during our first flight. We were not alone in our interest in these unique formations. We were joined by sea turtles, dolphins, sharks, and whales with their newly born calves. Some of these animals even showed us how to gain access to the deep waters inside. We followed a pod of dolphins through a small channel, just deep enough for us to scrape through in a small tender vessel. Once inside, we mapped the structure of the holes, retrieved samples and deployed sensors to characterize the conditions, while OceanXplorer deployed its submersibles and robots to explore the holes’ deep outer walls. On the outside, shallow coral reefs support a diversity of marine life. Inside, the deep water plummets to 50 meters and the outside walls extend 300 meters below the sea’s surface. The deep-sea vehicles gathered the first images of coral reefs hidden deep below the surface, reaching down as far as 130 meters. Some marine species cannot be seen with deep-sea vehicles due to their elusive nature. We used advanced technologies to extract DNA from the water samples to catalog the marine life that makes its home in these unique ecosystems. I had the honor of leading the research team that discovered the blue holes alongside renowned scientists Dr. Mohammed Qurban, CEO of the National Center for Wildlife, and Prof. Carlos Duarte, the scientific coordinator for the expedition. Their strong leadership forged a multinational, collaborative environment. Aligned with the Kingdom’s Vision 2030 goals, the National Center for Wildlife is leading the initiative to expand Saudi Arabia’s protected marine areas to include these unique ecosystems. The blue holes’ discovery solidifies Saudi Arabia’s status as a world-class ecotourism destination and global leader in marine conservation. • Shannon Klein is a research scientist in the Tarek Ahmed Juffali Research Chair in the Red Sea Ecology research group at KAUST who focuses on environmental change in the world’s oceans and solutions for rebuilding tropical marine life. X: @Dr_ShannonKlein