UFO Whistleblower David Grusch Claims ‘Multiple City Blocks’ Underwater Base With One Crucial Admission

Former Air Force intelligence officer and UAP whistleblower David Grusch has claimed people in the underwater community described a large ‘base of operations’ beneath the ocean that he said was ‘multiple city blocks’ in scale.

Grusch made the remarks during an interview with Joe Rogan, host of The Joe Rogan Experience, published on September 30, 2026. He said the account involved ‘sensitive Navy underwater things’ and that he did not know when the alleged structure arrived. He also said its origin was ‘indeterminate’ and that he was ‘not privy’ to further information.

Grusch Said ‘Stuff Comes And Goes’ From The Alleged Base

Rogan asked whether the alleged underwater site was a waypoint. Grusch replied: ‘It’s like a base. Stuff comes and goes.’

Grusch said people he knew from the underwater community had compared the account with The Abyss, the 1989 science-fiction film starring Ed Harris. He said those people considered the film ‘kind of a docudrama’ and referred to ‘large stuff down there’.

Rogan asked whether behavioral analysis had been conducted and whether the mission had been worked out. Grusch said he did not know the answer and was ‘as curious as anybody’.

The exchange did not identify a location or provide a document, image or other public record establishing the alleged installation. Grusch was also asked about the Baltic Sea anomaly, a sonar image publicized in 2011 that has prompted speculation about an underwater structure. He said there was ‘some interesting stuff there’ but that he would ‘allow the federal government to deal with that one’.

The Underwater Claim Was Not In Grusch’s 2023 Hearing

The underwater account was not part of Grusch’s public testimony before a House Oversight subcommittee on July 26, 2023.

Grusch, a former National Reconnaissance Office representative to the UAP Task Force, testified alongside former Navy commanding officer David Fravor and former Navy pilot Ryan Graves. The hearing examined unidentified anomalous phenomena (UAP), the US government’s term for objects or events that cannot immediately be identified.

During the hearing, Grusch alleged that people he said were involved in government programs had told him about a crash-retrieval and reverse-engineering effort involving UAP. He also said he had been informed that recovered ‘biologics’ were non-human.

The underwater-base account was instead presented during the September 30 podcast as information Grusch said he had heard from people in the underwater community.

AARO Found No Verifiable Evidence Of Extraterrestrial Technology

The Pentagon’s All-domain Anomaly Resolution Office (AARO), the office responsible for investigating UAP reports, published the first volume of its Historical Record Report in March 2024.

AARO said it had found no verifiable evidence that the US government or private companies had access to or were reverse-engineering extraterrestrial technology. It also said no US government investigation or official review had confirmed a UAP sighting as extraterrestrial technology.

The report assessed alleged hidden UAP programs as nonexistent, misidentified national-security programs unrelated to extraterrestrial technology, or discontinued programs. Its review covered historical US government investigations and included records and interviews relating to claims of secret UAP programs.

AARO’s report did not specifically examine the underwater-base account Grusch described on Rogan.

Grusch Gave No Location Or Measurement

Grusch said information about tracking the underwater activity involved sensitive national-security matters. He also indicated that the US government might know more than he does, saying: ‘I’m sure we know a little bit more. I’m not privy to that.’

The ‘multiple city blocks’ description was Grusch’s comparison of the alleged site’s size. He did not provide a measurement or say that he had personally surveyed the structure.

The interview provided no location, date, document or image establishing the alleged base.