Unidentified Submersible Objects (USOs) refers to any object or phenomenon detected underwater that cannot be immediately identified or explained. The term is similar to UFO/UAP but applies specifically to subsurface or underwater contexts. From medieval chronicles to present day Navy radar logs, witnesses have reported observations both with the naked eye and through sensors like sonar. They are often described as moving at extraordinary speeds, taking sudden changes of direction with impossible precision, and moving between water and air without leaving a ripple, “transmedium” capabilities.

Because we have less capability to maneuver quickly in the ocean, these objects are even harder to track and arguably more elusive than even airborne UAP. The ocean is often described as Earth’s last frontier. It covers more than 70 percent of the planet, and remains one of the least explored environments. So it is unsurprising that its mysteries have fueled both science and legend for centuries. Sailors once spoke of the Kraken, and it was dismissed as myth until 2012 when scientists finally captured footage of a giant squid. That breakthrough, achieved after weeks of deep dives and advanced imaging, was a reminder of how much remains hidden beneath the ocean surface.

Cambridge biologist and former Naval Intelligence officer Ivan T. Sanderson estimated that more than half of all UAP encounters occur over or near bodies of water. Since humans primarily live and observe from land, it is impossible to say for sure how prevalent USOs are. Those that have been spotted are typically around naval training ranges, offshore energy facilities, and critical shipping lanes – correlation or causation is unclear.

Unexplained objects operating in or near strategic maritime zones pose security challenges. The world’s oceans are home to critical undersea cables, nuclear submarines, shipping corridors and offshore energy infrastructure, all assets vital to global stability. Any object capable of moving undetected through these environments should be taken seriously. Understanding and monitoring USOs is therefore not just a matter of scientific curiosity but essential to protecting national security.

Historical Context

For centuries, sailors, naturalists, and chroniclers have recorded unusual lights and objects seen rising from, plunging into, or hovering over the sea. These reports stretch back nearly a thousand years and span multiple continents.

• 1067, England – Chronicler Geoffrey Gaimar wrote that locals saw a fiery object that “revolved, ascended on high, and then descended into the sea,” repeatedly reappearing off the Northumberland coast.

• 1803, Japan – The Utsuro-bune legend tells of a “hollow boat” with strange markings that washed ashore before vanishing back into the ocean.

• 1813, USS Niagara – Sailing between Lisbon and New York, the crew reported seeing a "large hump" they initially thought was a shipwreck. As they drew nearer, it appeared to be a "shell-shaped floating object" roughly 200 feet in length, with motion and a large arch-like opening covered at times by a fin. The crew considered sending a boat to investigate but were deterred by the “dreadful appearance of the monster.”

• 1825, HMS Blonde – English naturalist Andrew Bloxam described a red, luminous orb rising from the sea. He wrote that it was “the color of a red-hot [cannon] shot” and bright enough that “a pin might be picked up on deck.” The orb rose and fell twice before vanishing from sight.

• 1870, Atlantic crossing – Captain Frederick William Banner and his crew observed a light gray “circular cloud” with rays and appendages, moving unusually low over the ocean. Banner noted its structured, geometric form, including a fifth ray with a curved end, before it disappeared toward the northeast.

Illustration of the utsuro-bune from Bakin Kyokutei's Toen shōsetsu (1825)

U.S. Navy Sightings

One of the most notable modern USO encounters took place in 2004, when U.S. Navy officers aboard the aircraft carrier USS Nimitz , off the coast of San Diego, detected a disturbance in the ocean’s surface and then observed a white, Tic Tac–shaped object darting across the water at remarkable speed.

A decade later, Navy aviators on the East Coast reported seeing unusual objects “almost daily” at altitudes ranging from sea level to 30,000 feet. They described the objects as capable of accelerating, slowing down, and abruptly shifting to hypersonic speeds.

In 2019, U.S. Navy personnel aboard the USS Omaha near San Diego recorded video of multiple unknown aerial objects swarming around the vessel at speeds reportedly reaching 138 knots. One spherical object was tracked on radar before appearing to dive into the ocean and vanish, prompting the crew to prepare a helicopter launch. That same year, sailors aboard the USS Russell captured infrared footage of several objects hovering above the vessel at night. The lights appeared to pulse and maintain formation before disappearing into the clouds. The Pentagon later confirmed the authenticity of the footage, noting that it was part of an ongoing investigation by the Navy’s Unidentified Aerial Phenomena Task Force (UAPTF).

These were not the first anomalous encounters recorded by the Navy. In 1963, during training exercises off the coast of Puerto Rico, a Navy submarine reportedly broke formation to pursue a USO moving at speeds exceeding 150 knots, nearly four times faster than any known underwater technology of the era. The crew’s sonar systems tracked the object for four days as it dove to depths of 27,000 feet, but the object was never identified.

Navy personnel have long acknowledged that the ocean holds unexplained phenomena. Veteran sonar operator Aaron Amick has noted that unusual “fast mover” contacts occasionally appear on sonar, but they are “so quick that you can’t measure the speed. There is no way to measure the speed accurately because there isn’t enough data… I agree it’s odd. There are a lot of odd things in the ocean.”

Still frame from the 2004 USS Nimitz Encounter

In his November 2024 testimony before the House Oversight Committee, Former Naval Rear Admiral Tim Gallaudet made it clear that he sees these objects and incidents as a serious national security risk. He recounted an urgent warning sent out on the Navy’s secure network by an operations officer during 2015 exercises involving the USS Roosevelt off the East Coast. The message read:

“URGENT SAFETY OF FLIGHT ISSUE – If any of you know what these are, tell me ASAP. We are having multiple near-midair collisions, and if we do not resolve it soon, we will have to shut down the exercise.”

USS Omaha video captures a USO flying, hovering and splashing into the ocean.

Theories

Theories on what USOs could be span a wide spectrum:

• Known Natural Phenomena: Some believe USOs may be explained by sensor blips or misreadings caused by marine life such as whales or sharks interfering with sonar systems. Others point to unusual plasma effects, underwater turbulence, or forms of bioluminescent marine life that science has not yet fully documented.

• Advanced Civilization Technology: Some suggest USOs represent advanced technology either from an unknown otherworldly source or from an ancient Earth-based civilization hidden within the oceans. A subset of theories point to the idea of undersea bases, such as the much-debated Sycamore Knoll geological formation. Harvard theoretical physicist Avi Loeb has drawn on the work of MIT professor Sara Seager, who proposed that extraterrestrial probes might detach from “parent crafts,” recharge their batteries, and use liquid water as fuel. If true, Earth—with its abundant surface oceans—would be a natural target.

• Stealth Defense Technology: Another explanation is that USOs are classified military projects under active development by major powers. China has fielded the supersized drone submarine HSU-001 , spotted near Hainan Island. The UK has invested in XLUUV (extra-large uncrewed underwater vehicles). In the U.S., DARPA’s Manta Ray program is building advanced undersea vehicles, while militaries globally continue to test supercavitating torpedoes that travel at extraordinary speeds by creating a bubble around the projectile. Russia’s Poseidon hypersonic supertorpedo , stretching 24 meters, is one of the most striking examples.

Challenges in Studying USOs

• Limited Ocean Mapping: Less than 20% of the ocean is mapped in detail.

• Poor Visibility: Water absorbs light and radio waves, making detection harder.

• Classification & Secrecy: Many naval encounters are not publicly released.

• Confounding Variables: Difficult to rule out marine life, geological events, or human activity.

While the origins of USOs remain uncertain, their consistent characteristics and recurring presence near strategic waters make them impossible to dismiss. Continued research, combining naval data, scientific inquiry, and technological innovation are needed to drive answers.

Below you will find Enigma’s recent USO sightings and summary analysis.

Enigma Insights

As of August 2025, the Enigma network has logged over 9,000 U.S. sightings within 10 miles of shorelines and major waterways. Approximately 1,500 of those reports specifically mention “water,” “ocean,” “lake,” or “beach” (≈17%), and roughly 500 of those occurred within 5 miles of a coastline (≈5.6% of the total). More than 150 reports describe objects hovering above or ascending into or descending from bodies of water. The U.S. states with the most USO reports are California (389) and Florida (306), which is not a surprise, given they have large coastal populations.

Below are highlights from the community’s eyewitness accounts. Several reports come from aviation professionals and military veterans; many describe glowing metallic or silver spherical objects that appear to spin or move in formation, hover for extended periods, and maneuver near restricted airspace.

Swipe to explore select eyewitness testimony:

Enigma ran a statistical analysis across the community’s accounts:

The majority of sightings occur in the early morning, between 5–10 AM.

Regional Breakdown

USOs have been frequently reported across the U.S. Below is a sample set across key coastal regions. USOs have been frequently reported across the U.S. Below is a sample set across key coastal regions (all sightings reported within 1 mile of water).