The building, expected to house about 2,000 workers when it opens in 2021, was seen by some as a sort of silver medal for Boston in last year’s chase for Amazon’s hotly sought “second headquarters,” which the company decided to put outside of Washington, D.C.

Governor Charlie Baker and Mayor Martin J. Walsh joined Amazon executives to publicize a 17-story, 525,000-square-foot building in Seaport Square. Amazon has leased all of the building’s office space, with an option to lease a second similar building that has been approved next door, as the e-commerce giant expands its so-called tech hub in Boston.

Amazon on Tuesday celebrated the start of construction on what will be its biggest, most visible building yet in Boston: a glassy new midrise office in the Seaport.


The company, though, said it had always planned to keep growing in Boston and Cambridge, regardless of the second headquarters decision. Mike Touloumtzis, the engineer who leads Amazon’s local technology offices, on Tuesday repeatedly pointed to the region’s highly educated population as a reason why.

A temporary event tent sat surrounded by new towers in the Seaport District on the site where Amazon will build. Lane Turner/Globe Staff/Globe Staff

“Amazon is investing millions in Massachusetts and the Greater Boston area because of the exceptionally talented workforce that exists here,” he said. “But talent alone will not enable us to continue to grow.”

Touloumtzis laid out a number of investments the company is making, including funding computer science classes at 35 high schools in the area. But Amazon also received state and local subsidies for its new building: The city awarded a $5 million break on property taxes over 15 years, while the state will finance $20 million in infrastructure improvements around the building that the developer, WS Development, had previously agreed to pay for.

People familiar with the deal said those savings would be passed on to Amazon in the form of lower rent. Both incentives are contingent on Amazon’s creating jobs in the Seaport and elsewhere in Greater Boston in coming years.


Amazon's Michael Touloumtzis. Lane Turner/Globe Staff/Globe Staff

Longer-term, Amazon has not decided whether to lease the second building at Seaport Square, Touloumtzis said, but continues to expand its tech workforce here, filling a new 900-person office on nearby Melcher Street in Fort Point and maintaining its large presence in Kendall Square in Cambridge.

While a number of other large tech companies are hiring rapidly in Boston, Touloumtzis said, Amazon has had little trouble finding workers.

“We think this is a great place to be,” he said.

Tim Logan can be reached at Tim.Logan@globe.com. Follow him on Twitter at @bytimlogan.