Every Conspiracy About Underwater UFOs Explained

There's a reason that many UFO enthusiasts treat them as possible alien visitors. The "F" in Unidentified Flying Objects rather pointedly directs the interested upward. Science fiction and paranormal investigators alike urged mid-20^th-century readers to "keep watching the skies." And those with abduction stories describe being taken up and away.

Such stories (and a plethora of books, films, and TV shows) have made UFOs the most famous of mysterious objects buzzing about the modern world. But they have a counterpart down here on Earth — specifically, under the seas. There are numerous reports of what have been dubbed Unidentified Submerged Objects, or USOs. It's a term not exclusive to mystery craft; the U.S. Naval Institute has written about several encounters with USOs that were unknown or rarely-seen sea beasts. But there have also been reports of strange lights or ships prowling the deep waters of the world, sometimes even transitioning from the sea to the skies or vice versa.

USO sightings haven't just been a matter of strange or exciting encounters either. Like with the UFO phenomena, they've sparked a rush of conspiracy theories. Aliens are in that mix, naturally, but there are also covert programs and government cover-ups to fret about too. We'll do our best to briefly explain the alleged conspiracies about USOs.

It should be no surprise that USOs are assumed by some to be alien crafts just as UFOs are. It might be more surprising to learn that a proponent of those theories is a sitting United States congressman. But Tim Burchett (R-Tenn.) has been making such claims since at least 2023. Per Newsweek, he's alleged that he has intelligence ("I've been told," he said) that government and industry have their hands on alien technology and are working to reverse engineer it.

Among the claims that Burchett has heard that he's passed on as a representative is that of a USO "as large as a football field" moving at hundreds of miles an hour. This story was allegedly shared by an admiral. If there was any doubt as to what Burchett thought such a craft was, he said in 2025 that he thinks it's likely that USOs are alien ships using underwater bases in their light-speed travels. But Burchett is banking on these visitors from the stars being friendly. "I mean, with that [sic] capabilities, they would have barbecued us a long time ago," he told One America News (via CBS News).

Congressman Tim Burchett takes a benign view toward the intentions of hypothetical alien visitors who cruise our oceans with USOs. But not everyone is so sure that the beings they assume operate these craft come in peace. There are those who worry that critical underwater infrastructure could be threatened by USOs.

That's a concern shared by retired Rear Admiral Timothy Gallaudet, who is also a prominent ufologist. He's expressed worry about American maritime security independent from unidentified objects; there are many mysteries of the ocean, and a lack of knowledge about what's down there means there are unknown risks. But in a white paper for the Sol Foundation, Gallaudet specifically raised the issue of USOs entering American waters as a major danger and suggested that the U.S. government had not disclosed everything it knew about them. Elsewhere, he claimed that these vehicles couldn't possibly be experimental military aircraft because their behavior was too fast and too dangerous for any known vehicle.

With all that said, Gallaudet ended his white paper with an appeal to the scientific possibilities of devoting more resources to USOs and other unidentified objects. He endorsed the claims of eyewitnesses that the craft move in ways that defy our understanding of physics and wrote that being able to acquire such technology could revolutionize fields across the civilization spectrum, maritime defense very much included.

The extraterrestrial hypothesis for UFOs, USOs, and other craft grouped into the "Unidentified Anomalous Phenomena" category is by far the most famous. But if aliens aren't your speed, why not try out a cryptid? In a 2024 edition of Philosophy and Cosmology, a group of authors put forward what they called the "cryptoterrestrial hypothesis:" that UAPs, including USOs, come from earthbound beings that have, as of yet, gone undetected by modern civilization.

The paper, which was by its own admission speculative in nature, put forward four possible cryptoterrestrial explanations for UAPs: an ancient, technologically advanced human society that was destroyed and lingers on in remnants; a non-human advanced civilization, possibly descended from a non-hominid species (theropod dinosaurs were offered as a possibility); aliens or time-travelers that ended up stuck on Earth and have continued to live stealthily with their advanced technology; and supernatural entities, what could be described as fairies or angels.

The authors of "The Cryptoterrestrial Hypothesis" offered up conjecture and anecdotal evidence for all four possibilities. But it's worth noting that even they acknowledged that unknown earthly entities are lower on the likelihood ladder than other explanations for UAPs. It's worth noting, too, that USOs in particular have no photographic or video evidence to back up any theory about them, be it out-of-this-world or rooted here at home.