"Google Barge ... A floating data center? A wild party boat? A barge housing the last remaining dinosaur? Sadly, none of the above," the company said in an email Wednesday to CNN.
"Although it's still early days and things may change, we're exploring using the barge as an interactive space where people can learn about new technology," the statement said.
A four-story structure made from shipping containers sits atop the barge docked at a pier on the bay's Treasure Island, and three similar vessels have been seen across the country, including one in the harbor at Portland, Maine.
Google's statement has confirmed what many had suspected, that the mystery barge would serve as a floating showroom for upcoming products like the company's Google Glass connected eyewear.
The barges are also an effort by Google to compete with rival Apple's stylized retail stores for consumer attention, a source told KPIX-TV in San Francisco.