Atomarine, a Cambridge, Massachusetts-based startup building floating data centers powered by nuclear reactors mounted on ships, has raised USD 19 million in a seed round.

The round was led by Y Combinator, with participation from Pantera Capital, Soma Capital, Seven Seven Six, Liquid 2 Ventures, Audacious Ventures, and E14 Fund.

150 MW nuclear-powered offshore data centers

The company's plan is to mount small modular nuclear reactors (SMRs) on vessels that would power floating platforms of modular data centers, serving AI compute offshore.

According to Atomarine, its nuclear ships would eventually be capable of delivering 150 MW of power, which the company says would be enough to run two such platforms. A first deployment is targeted for 2031 or 2032.

A startup born at MIT

Atomarine was founded by MIT students Dimitris Koutentakis and Emile Germonpré.

The pair have set out to address the growing demand for AI compute capacity by relocating data centers away from land and onto ships stationed at sea. Koutentakis, earlier this year, explained the company's thinking on timelines for reactor access.

"We've been talking to some potential partners about getting access [to an SMR]," he said.

"But with the minor engineering changes that would be required and the regulatory timelines, we're targeting a first deployment in 2031 or 2032."

Natural gas as the bridge fuel

While nuclear power is the end goal, the company's early vessels will not run on reactors. No SMR has yet reached the market: none of the vendors working in the space have released a commercial model or achieved regulatory approval in the US or any other market.

As a result, Atomarine intends to rely first on natural gas generators mounted on its ships, with nuclear power to follow once SMRs become commercially and regulatorily available.

The gap between the company's initial gas-powered deployments and its eventual nuclear fleet is reflected in the 2031–2032 target date for a first deployment, a timeline Koutentakis tied directly to the engineering modifications and regulatory processes involved in securing access to an SMR.

The case for taking compute offshore

Writing on LinkedIn after the funding announcement, Koutentakis made the case for locating data centers at sea rather than on land.

"By moving offshore, we do not compete with communities for water, power, or land, and we do not drive up their electricity bills or rent," he said.

He argued that this positioning serves both national and environmental objectives. "This allows America to stay competitive in the AI race without putting the burden on local communities, while fighting climate change by scaling AI on nuclear instead of fossil fuels," Koutentakis wrote.

The company is not starting from zero on technical development, according to its co-founder.

"We have already built a functional proof of concept, and we are now racing towards our next big milestone," Koutentakis said in the same post. He did not specify what that next milestone entails.

Recruiting across three disciplines

With the seed round in hand, Atomarine is turning to recruitment.

Koutentakis said the company is hiring engineers with specialisms in naval architecture, nuclear, or data center design, a hiring profile that mirrors the three domains the company must bring together to mount reactors and compute platforms on seaworthy vessels.

Compute at sea attracts a field of competitors

Atomarine is not alone in pursuing offshore AI infrastructure. It is one of numerous companies, in the US and around the world, working to put AI compute at sea.