BOSTON—Skanska USA Commercial Development broke ground on Wednesday on the $281-million 121 Seaport office tower here, the third major project the New York-City based firm is building in Boston.

The 121 Seaport building, when completed in early 2018, will be a 17-story, 400,000-square-foot building that will also feature two floors of retail and two below grade parking levels. Skanska says that the building, located in the heart of the city's Seaport District, will be designed to achieve LEED Platinum certification.

Sweden-based Skanska announced on Wednesday it is investing $281 million in a new office building in Boston. A company spokesperson confirms that the investment is going towards the development of 121 Seaport. Skanska USA Building is the construction manager for the project and will add a contract value of $150 million in order bookings for the third quarter of 2015.

“It is a top priority for us to design world-class office buildings like 121 Seaport that can attract talented, bright minds that have helped solidify Boston's international reputation as an intellectual, forward-thinking city,” said Shawn Hurley, executive vice president for Skanska USA Commercial Development in Boston. “We recognize and have seen first-hand how companies succeed when employees thrive in their work environments. We've designed 121 Seaport to match how people work best in what is fast becoming Boston's most desired neighborhood to live and work in.”

Boston Mayor Martin Walsh said at the groundbreaking event, “The development team has clearly put a lot of thought into making 121 Seaport a place where people get excited about going to work. Put that atmosphere together with the building's sustainable features, and you get a truly unique development in one of the fastest growing areas of our city.”

Among the building's sustainable features include a 40,000-gallon tank rainwater reuse system, reducing its water use by approximately 30%. The building will also include an efficient chilled-beam mechanical system, which was first pioneered in Boston at Skanska's 101 Seaport property. The system circulates water rather than air for building cooling, significantly reducing energy usage, company officials say.

Other notable features at 121 Seaport will be virtually column-free floor plates, elevated 10-foot ceiling heights and high-performance vision glass to enhance natural daylight into the building's office spaces while offering views of Boston Harbor and the Financial District. Additional amenities include outdoor terraces on the third floor rooftops as well as a private, tenant-only fitness center.

A three-story lobby, with ultra-clear vision glass, will face Seaport Square Green and Boston Harbor while the entrance will open to Harbor Way, an expansive 70-foot-wide pedestrian retail promenade with approximately 15,000-square feet of tree-lined open space at the building's base.

Skanska has two other major projects in development in Boston.101 Seaport, a 17-story, 440,000-square-foot office tower with 20,000-square-feet of ground floor retail, is under construction and slated for completion in October 2015. The building will be home to PwC's new headquarters. PWC will occupy 75% of 101 Seaport. Watermark Seaport, a 300,000-square-foot residential building with ground floor retail, is also under construction. Pre-leasing scheduled to begin this fall on the project that is expected to be finished sometime in 2016.