OAKLAND — Visitors and residents can soon get free tours of the Port of Oakland’s shoreline.

The port’s free tours of the harbor will begin in May and go through October, marking the third season of the popular sightseeing tours.

The port signed an agreement with San Francisco-based Blue & Gold Fleet, a popular operator in San Francisco Bay excursions, to run 12 cruises through October.

The port said nearly 1,200 passengers sailed on harbor tours last year, and it expects to attract 3,000 visitors in 2017 by using larger vessels. Blue & Gold will deploy boats that hold 230 passengers for the 90-minute tours, bigger than the boats in previous seasons that held 130 people.

“People from around the world come to see the Port of Oakland up close,” said Amy Tharpe, the port’s social responsibility director, in a news release. “Blue & Gold vessels will give them the birds-eye view, and we’re thrilled to be working with them.”

Oakland’s waterfront has long been a popular destination for tourists, but it has picked up in recent years, thanks to upticks in leisure and business travel to the East Bay. Last year, the port’s Jack London Square attracted a record 3 million visitors.

Every harbor tour has sold out since the excursions began in 2015. The tours follow the port’s shoreline along Oakland Estuary and Outer Harbor, and passengers will be able to see into working Oakland marine terminals from the upper decks of the boats. Live narration will accompany the tours.

The port will host two harbor tours a month on Fridays at 6:45 p.m., which depart from Jack London Square’s ferry dock at the foot of Clay Street. Ticket registration begins May 1 on the port’s website, and the first tour is slated for May 12.

More information, schedules and tickets can be found at the Port of Oakland website.