While Boston eagerly awaits news from Seattle regarding the final contenders for Amazon HQ2, the tech giant is already on the hunt for a hefty amount of office space in the city’s Seaport neighborhood.

Amazon and Chestnut Hill-based WS Development are in negotiations for a 500K SF office in the Seaport. The company would have the option to take a second building, bringing the total size to 1M SF. The first phase of HQ2 calls for a 500K SF office by the end of 2019. The Seaport office search began before the company announced in September it was looking to build a second headquarters, the Boston Globe reports.

Amazon is focusing on Seaport Square, and a decision should come around the same time it is expected to reveal finalists for HQ2. WS revealed plans last summer for a 499K SF office building at 88 Seaport Blvd. on the site of the old Our Lady of Good Voyage chapel. The developer won city approval last fall for 2.8M SF of office space on four blocks at Seaport Square.

While it is not clear if the potential WS deal is tied to HQ2, Seaport Square is too small for the overall 8M SF intended for HQ2. Boston’s official bid identifies Suffolk Downs in East Boston as its preferred site, but a conglomeration of several properties from South Station into the Seaport were identified in the bid as a possible home for Amazon’s second headquarters.

Even without HQ2, Amazon has grown significantly in Greater Boston. In the five years since first opening an office in Kendall Square, the company has grown to house 700 employees at 101 Main St. in Cambridge. It also has an office at a WeWork in Back Bay.

It announced in July it was taking 150K SF at 253 Summer St. in nearby Fort Point and planning on hiring an additional 900 employees on top of its existing local headcount of over 1,000.