The agreement represented the largest single procurement of renewable energy by a U.S. state so far, according to a statement from New York Governor Andrew Cuomo's office.
As part of the deal, Equinor will invest an undisclosed sum to help upgrade two ports, the Port of Albany and South Brooklyn Marine Terminal, to support the expected boom in the nascent U.S. industry.
The United States lags Europe in development of offshore wind energy, with just one small wind farm off Rhode Island. Permits for the first major project, Vineyard Wind, has suffered a string of setbacks, but several Northeastern states have set targets to procure large amounts of offshore wind over the next 15 years.
Equinor's two projects, Empire Wind 2 and Beacon Wind 1, will provide 2,490 megawatts of power to New York state under the contract announced on Wednesday, enough to power about 1.3 million homes.
New York has a goal of sourcing 9,000 megawatts of offshore wind by 2035 as part of Cuomo's plan to address climate change.
Equinor has a prior commitment to provide 816 MW of power to New York from another offshore wind project, Empire Wind 1.
In September, Equinor said BP would be a 50% partner in the two projects. That deal is expected to close early this year.
In a statement, Equinor Chief Executive Anders Opedal called the successful bids "a game-changer for our offshore wind business in the U.S."
European oil firms such as Equinor and BP are under pressure from activists, banks, investors and some governments to shift away from fossil fuels, and analysts say offshore wind farms are probably the quickest way for them to do so.
(Reporting by Terje Solsvik in Oslo and Nichola Groom in Los Angeles; editing by Nerijus Adomaitis and Grant McCool)