Unclassified // open-source data on US defense tech // 14 NOV 2026
Maritime
11 companies

Maritime Defense Companies in the United States

Uncrewed surface and undersea vessels, the autonomy that runs them and the yards that build them. The Navy wants a hybrid fleet with large numbers of uncrewed ships, and US shipbuilding capacity is a known bottleneck, which is where several of the best-funded startups are aiming. Together they have disclosed $3.4B in funding, led by Saronic (~$2.6B). The newest round on record is Corridian's Seed (Nov 2026).

Autonomous reconnaissance craft in the Baltic Sea, BALTOPS 2025. Photo: U.S. Navy photo by Petty Officer 2nd Class Ryan LeCompte, Public domain (PD-USGov-Military-Navy).

Latest rounds

DateCompanyRoundAmountHQSector
Nov 2026Corridian Seed$38MBoston, MAMaritime
May 2026HavocAI Series A$100MProvidence, RIMaritime
Apr 2026Ulysses Series A$38MSan Francisco, CAMaritime
Mar 2026Saronic Series D$1.75BAustin, TXMaritime
Feb 2026Seasats Series A$20MSan Diego, CAMaritime
Dec 2025Vatn Systems Series A$60MBristol, RIMaritime
Oct 2025Saildrone Corporate round$50MAlameda, CAMaritime
Oct 2025Albacore Seed$6.5MPhiladelphia, PAMaritime
Sep 2025Blue Water Autonomy Series A$50MBoston, MAMaritime

All companies

Full directory

Corridian

Boston, Massachusetts

Builds ultra-large autonomous underwater vehicles that haul containerized payloads over thousands of nautical miles for undersea logistics.

MaritimeSeed / Nov 2026

HavocAI

Providence, Rhode Island

Develops autonomy software and fleets of autonomous surface vessels for naval missions, with collaborative control across sea, air and ground platforms.

MaritimeSeries A / May 2026

Ulysses

San Francisco, California

Builds low-cost Mako underwater drones, the Leviathan surface mothership and the Kraken recovery system for ocean ISR and seabed missions.

MaritimeSeries A / Apr 2026

Saronic

Austin, Texas

Builds autonomous surface vessels from small attritable craft to larger ships, with autonomy software and a dedicated shipyard for the US Navy and allies.

MaritimeSeries D / Mar 2026

Seasats

San Diego, California

Builds small solar-electric uncrewed surface vehicles, including long-endurance Lightfish and Quickfish boats, for maritime surveillance and security.

MaritimeSeries A / Feb 2026

Vatn Systems

Bristol, Rhode Island

Builds the Skelmir family of low-cost autonomous underwater vehicles that double as lightweight torpedoes, with GPS-free inertial navigation.

MaritimeSeries A / Dec 2025

Saildrone

Alameda, California

Builds wind and solar powered uncrewed surface vehicles, from the Explorer to the larger Surveyor and Voyager, for maritime surveillance and ocean data.

MaritimeCorporate round / Oct 2025

Albacore

Philadelphia, Pennsylvania

Y Combinator-backed maker of Ghostfin, an 8-foot autonomous mini-submarine with a 250-pound payload and about 1,000 nautical miles of range.

MaritimeSeed / Oct 2025

Blue Water Autonomy

Boston, Massachusetts

Builds long-range, fully autonomous ships of 100 to 150 feet designed from the keel up for US Navy fleet missions.

MaritimeSeries A / Sep 2025

Terradepth

Austin, Texas

Combines autonomous underwater vehicles with Absolute Ocean, a platform that fuses sonar and ocean data for near-real-time seabed intelligence.

MaritimeRound n/d

Sea Machines Robotics

Boston, Massachusetts

Makes autonomy and remote command systems that convert crewed vessels into uncrewed boats, plus the STORMRUNNER autonomous craft.

MaritimeRound n/d

Questions

Who are the biggest maritime defense companies in the US?

By disclosed funding among the companies we track: Saronic, Saildrone, HavocAI and Vatn Systems, as of November 14, 2026.

How many maritime defense companies are in the US?

Our directory lists 11 privately held US maritime startups as of November 14, 2026. Large primes and public companies are not included.