Fundraising Fox

Maritime Fusion

YC W25

San Francisco, US · Founded 2024 · 6 employees · Hiring · 4 known investors

Maritime Fusion designs and builds zero-emission fusion reactors for deployment in maritime transport and remote energy installations. The company aims to use these off-grid applications as a pathway to develop cost-competitive grid-scale fusion reactors.

Advanced ManufacturingCleantechDeep TechEnergyFusion EnergyHard TechUnited States of AmericaAmerica / Canada

Founders & leadership· Y Combinator alumni (W25)

Maritime Fusion was founded in 2024 by Justin Cohen and Jason Kaufmann.

JCJustin Cohen
Justin CoheninCo-FounderJustin Cohen is a nuclear engineer and plasma physicist who previously held roles at Tesla, SpaceX, Princeton Plasma Physics Laboratory, and NC State, as well as attended Columbia University. He now leads Maritime Fusion, developing fusion reactor technology.30 Under 30 2026
JKJason Kaufmann
Jason KaufmanninCo-FounderJason Kaufmann studied physics and computer engineering at Penn, and has worked on hardware engineering roles at Tesla focused on AI systems and at SpaceX on power systems for rockets. He is now developing fusion reactor technology for maritime applications.30 Under 30 2026

Investors · 4

Aera VCSingapore · $25K – $5M
Avant LabsBangkok
Trucks VCSan Francisco
Y CombinatorSan Francisco · $500K

Funding

SEC filings, press & company announcements

$9M disclosed across 2 rounds · 2025

Source: company announcements and press reports — follow each round's link for the claim.

Competitors · 1

by search overlap
Tri Alpha Energy3 shared keywordsTAE Technologies develops hydrogen-boron (aneutronic) fusion power using a beam-driven Field-Reversed Configuration reactor design, aiming to deliver utility-scale fusion electricity to the grid in the early 2030s. Through its subsidiaries, the company also works on grid energy storage solutions and cancer treatment technologies.

Companies competing with Maritime Fusion for the same Google search keywords, organic and paid, via search-intersection analysis.

In the news

Start-up company looks to develop fusion-powered ships -- ANS / Nuclear Newswireans.org · Nov 2025Maritime Fusion: $4.5 Million Raised To Advance HTS Cable Technology And Tokamak Reactorpulse2.com · Nov 2025Maritime Fusion Closes $4.5M Seed Round to Advance Fusion Propulsion | SignalBasetrysignalbase.com · Nov 2025Maritime Fusion Raises $4.5M in Seed Fundingfinsmes.com · Nov 2025Y Combinator-backed Maritime Fusion Raises $4.5M From Trucks VC, Paul Grahamfinance.yahoo.com · Nov 2025This startup wants to build a fusion reactor — on a boat | TechCrunchtechcrunch.com · Nov 2025Maritime Fusion - Fusion reactors for shipsycombinator.com · Feb 2025

Frequently asked questions

What does Maritime Fusion do?
Maritime Fusion designs and builds zero-emission fusion reactors for deployment in maritime transport and remote energy installations. The company aims to use these off-grid applications as a pathway to develop cost-competitive grid-scale fusion reactors.
Who founded Maritime Fusion?
Maritime Fusion was founded by Justin Cohen, Jason Kaufmann in 2024.
Who are Maritime Fusion's investors?
Maritime Fusion's investors include Aera VC, Avant Labs, Trucks VC, Y Combinator.
How much funding has Maritime Fusion raised?
Maritime Fusion has disclosed $9M raised across 2 rounds.
Where is Maritime Fusion headquartered?
Maritime Fusion is headquartered in San Francisco, US.