In this episode of the Voices from DARPA podcast, John Waterston (https://www.darpa.mil/staff/mr-john-waterston), a program manager since 2017 in the agency’s Strategic Technology Office (https://www.darpa.mil/about-us/offices/STO), lets listeners in on his oceanic immersions both as a naval officer and a technology developer. Now a commander in the U.S. Naval Reserve, John offers snapshots of living, working, and serving on our nation’s nuclear submarines before describing his current work at DARPA to develop technologies to better understand, monitor, and navigate the planet’s most prevalent environment—the oceans. In one of his ambitious programs, John seeks to deliver what has been a coveted but elusive capability—the equivalent of GPS that operates even in the deep ocean. In a related program, John explains how very low-frequency (VLF) electromagnetic signals from lightning that occurs relentlessly around the world can become a key to a back-up positioning, navigation, and timing (PNT) system in case our must-have GPS goes down. And in perhaps his most audacious program, the Ocean of Things (https://www.darpa.mil/program/ocean-of-things), he is assembling what amounts to an ocean-scale nervous systems comprising tens of thousands of floating sensors, opening pathways to an unprecedentedly fine-grained understanding of what is happening in vast ocean environments. Says John about the ocean, “it’s so immense, covering 70% of the Earth’s surface, yet even with all of the ships, all of the aircraft, all of the satellites, and all of the existing sensors, we are severely undersampling this environment.” He has made it his mission to fill in that data shortfall, which he says could significantly improve weather forecasting for the benefit of both military and civilian sectors.