Loch Ness 2025: The Quest Sonar Expedition Returns Anomalous Contacts

In late May 2025, the Loch Ness Centre at Drumnadrochit, in partnership with Loch Ness Exploration and a coalition of volunteer researchers, completed the second of its multi-year “Quest” expeditions: a coordinated, instrumentation-heavy survey of the Scottish Highland loch that has fascinated witnesses, researchers, and tourists since the modern era of Loch Ness Monster sightings began in earnest in 1933. The 2025 expedition, conducted from May 22 through May 30 along the loch’s twenty-three-mile length, recorded several substantial sonar contacts at depths consistent with the loch’s deepest basins. The contacts, which the expedition organizers were careful not to overinterpret, became the most discussed Loch Ness research outcome of the year and reignited debate about what — if anything — moves beneath the loch’s dark, peat-stained water.

A Loch Built for Mystery

Loch Ness occupies the central segment of the Great Glen Fault, a geological feature that bisects the Scottish Highlands from Inverness in the northeast to Fort William in the southwest. The loch is approximately twenty-three miles long, just over a mile wide at most points, and reaches a maximum depth of around 230 meters — making it the second-deepest loch in Scotland and, by volume, the largest body of fresh water in the United Kingdom. Its physical characteristics have always made it an unusual environment for systematic biological study. The water is dark with peat suspension, limiting visibility to a few meters even in the surface layers; the sediment-rich bottom is heavily folded with underwater ledges and crevices; and the loch’s narrow profile and steep sides make traditional sonar sweeps challenging to interpret.

The modern era of Loch Ness Monster reporting began with the 1933 sightings of George Spicer and his wife on the road above the loch, and the subsequent publication of the controversial Hugh Gray photograph and the still-disputed “Surgeon’s Photograph” of 1934. The decades since have produced a sustained record of eyewitness accounts, photographs of varying quality, the scientific expeditions of the Loch Ness Investigation Bureau in the 1960s and 1970s, and a series of sonar surveys whose results have ranged from the famous “Big Expedition” of 1987 to more recent efforts using modern multibeam sonar systems.

The 2025 Expedition

The 2025 expedition built on the inaugural Quest of 2023, which had produced four small but unexplained sonar contacts and had established a methodological template for the series. The 2025 effort substantially expanded the scope: twenty-two volunteer observers were stationed at fixed points around the loch with binoculars, telescopes, and high-resolution cameras; a research vessel equipped with multibeam sonar, side-scan sonar, and a hydrophone array operated continuously from a base near Urquhart Castle; and a small team of drone pilots conducted aerial surveys at scheduled intervals across the eight-day period.

The expedition’s instrumentation was deliberately diverse. The hydrophone array was tuned to detect underwater acoustic signatures that might indicate large biological activity, and recordings were processed through analytic software developed for marine mammal research. The multibeam sonar produced high-resolution depth maps and could detect objects in the water column with substantially greater precision than the older sonar systems used in earlier surveys. The aerial drones provided continuous photographic coverage of the loch surface during daylight hours, complementing the visual observations from the shore-based teams.

What the Sonar Found

The most discussed results of the expedition came from the multibeam sonar system. Over the course of the eight-day survey, the operators recorded several substantial sonar returns at depths between 120 and 180 meters in the loch’s deeper basins, including the central depression off Urquhart Castle and the deeper southern stretches. The returns were of a size and signature that the operators could not immediately classify. They were not the small, sharp returns characteristic of fish; they were not the elongated, structured returns characteristic of submerged tree trunks or other rigid debris; and they did not correspond, on subsequent review of contemporaneous shipping records, to any vessel or sonar shadow that could be confidently associated with known surface or subsurface activity.

The expedition organizers were careful in the language they used to describe the contacts. Alan McKenna, who has led much of the recent Loch Ness research from the volunteer side, described the returns as “anomalous” rather than indicative of any particular biological identity. The contacts, he noted, could plausibly correspond to large fish such as Atlantic sturgeon — a species that has been considered a candidate for at least some Loch Ness sightings — or to logs, debris, or other natural objects whose acoustic signatures the system had not been calibrated to recognize. They could equally correspond, he acknowledged, to something the available data could not yet identify.

The hydrophone array recorded a small number of acoustic signatures whose characteristics did not correspond to known biological or anthropogenic sources. These included low-frequency tones of brief duration, recorded on multiple instruments distributed around the loch, that the analysts could not attribute to vessel traffic, wave action, or geological activity. The recordings were submitted to specialists in underwater acoustics for further analysis, with results to be released in a subsequent technical report.

Visual Observations and the Public Record

Beyond the sonar findings, the expedition produced a substantial body of visual observation logs from the shore-based volunteer teams. Several observers reported sightings of unusual surface disturbances — V-shaped wakes, sudden patches of disturbed water, brief glimpses of dark shapes near the surface — that were photographed and documented. None of the visual observations rose, in the assessment of the expedition organizers, to the level of definitive evidence; they joined the long catalog of Loch Ness surface reports that constitute the modern body of Nessie evidence.

The 2025 expedition’s results, taken together, neither confirmed nor refuted the existence of any large unknown creature in the loch. They added to a documentary record that, for ninety years, has resisted both definitive proof and definitive dismissal. They also reinforced the methodological case that systematic, instrumentation-based survey work — conducted to scientific standards and reported transparently — represents the most productive way forward for a question that has often been treated, fairly or unfairly, as the exclusive domain of cryptozoological enthusiasm.

The Long View

The Loch Ness Centre’s commitment to the Quest expeditions as a recurring multi-year program is itself a development of some significance. The cryptozoological investigation of the loch had, by the early 2020s, become substantially less institutionally serious than it had been in the era of the Loch Ness Investigation Bureau. The Quest series, with its volunteer infrastructure, its methodological rigor, and its careful management of public communication, represents a return to a more disciplined approach. Whether subsequent expeditions yield definitive findings or merely add additional layers to an already complex record, the program has reestablished a tradition of patient, instrumented inquiry into one of the most enduring questions of modern cryptozoology.

The 2025 contacts, like the 2023 contacts before them, are unlikely to be the last word on what the loch contains. They are part of a longer story whose final pages, if such pages exist, remain unwritten.

Sources

• The Loch Ness Centre — Organizer of the Quest expedition series
• Wikipedia: Loch Ness Monster
• BBC News Highlands and Islands — Regional reporting on the 2025 expedition