The $645 million, 390-foot “Breakthrough” superyacht that’s long been linked to the billionaire and philanthropist is up for sale by yacht broker Edmiston. 

Jamie Edmiston, CEO of his namesake company, said in a statement it’s “the most extraordinary yacht ever built [and] the one that will change it all.”

Neither Gates nor Edmiston responded to requests for comment from Fortune, but it’s been widely reported across business and industry-specific publications the superyacht was commissioned by Gates just a few years ago. 

Dutch shipyard Feadship spent five years building “Breakthrough,” also known as “Project 821,” and it’s large enough to accommodate 43 crew members and 30 guests across 15 cabins. Forbes Australia reported in May 2024 the yacht also features a hospital, library, elevator, movie theatre, pool, hot tubs, steam room, gym, separate owners’ deck with two bedrooms, two bathrooms, two offices, and 14 slide-out balconies. 

“The big deal about Breakthrough is that it’s a modern engineering marvel, period,” Brad Hall, CEO of online yacht marketplace Yachtlify, told Fortune.

That’s because the “Breakthrough” is the world’s first hydrogen fuel-cell superyacht. And that’s what makes the superyacht particularly expensive, Heigo Paartalu, CEO of YachtWay, told Fortune.

“Breakthrough—true to its name—is a genuine breakthrough and milestone in innovation,” said Paartalu, who heads up what can be compared to the Zillow for yachts. “It’s the only privately owned vessel powered by hydrogen, and building one demands extreme precision, as any hydrogen leak could be catastrophic.”

Video footage courtesy YachtWay.com.

There are very few shipyards in the world capable of building a vessel like this, Paartalu explained, and he said “it’s no surprise” Feadship pulled it off, as it’s widely considered one of the best shipyards globally.

While most yacht owners prioritize maximum interior space, “Breakthrough” was primarily designed with the climate in mind, Paartalu said. Its engine room takes up significantly more space than traditional yacht propulsion systems. 

“It’s a pretty bold, uncompromising choice,” Paartalu added. Gates is also heavily involved in clean energy projects like Breakthrough Energy, which supports early-stage companies developing technologies to reduce greenhouse gas emissions.

And because superyacht builders are backed up with production schedules, anyone looking to buy the “Breakthrough” should be expected to pay a premium, Paartalu said, rather than waiting four-to-five years for a new build.

“Time is priceless at this level,” he said. “Many buyers prefer immediate gratification over a multi-year wait.”

What’s also interesting about the sale of “Breakthrough” is Gates reportedly never even stepped foot on the yacht, even though it’s up for sale and will be shown at the Monaco Yacht Show in September.  

While every superyacht is unique, Paartalu said, in this case, the new owner will be buying more than a boat. 

“You’re buying future-forward technology and a benchmark in innovation,” he said. “Add to that a pedigree few can match. And let’s be honest: How often can someone say, ‘I bought Bill Gates’ yacht?’”