United States-based United Airlines has been given permission to fly the Dreamliner again by the Federal Aviation Administration (FAA).
The FAA has issued a formal air worthiness for US airlines, with other regulators around the world now expected to follow suit.
The US directive allows airlines to resume flights provided their battery systems are replaced.
Ethiopian Airlines has also confirmed it will become the first carrier to resume flying the 787 Dreamliner, with a commercial flight on Saturday to neighbouring Kenya.
It comes a week after the FAA allowed Boeing to replace battery systems with a new design.
All 50 787s in service were grounded in January over safety concerns.
United Airlines is currently the only US airline with 787s in its fleet.
A United statement said: “This is a good step forward.
“We are mapping out a return-to-service plan, and we look forward to getting our 787s back in the air.”