Employees of shipmaker Harland and Wolff cheered as they strode through the gates for their first day back at work in weeks.
The future of the Belfast shipyard - where the Titanic was built - had been in serious doubt after it was placed into administration over the summer.
Workers had led a nine-week campaign to occupy the site to save it from closure.
But they claimed victory earlier this week when it was announced London-based company InfraStrata had purchased Harland and Wolff for £6 million
It meant all 79 workers who did not take a voluntary redundancy when the yard went into administration could return to work.
Steel worker and GMB shop steward Barry Reid said he had prayed this day would come.
“Everybody is ecstatic at what has happened, we believed in ourselves, we believed in the company, we have been proved right,” he said.
Shadow Northern Ireland secretary Tony Lloyd and Ulster Unionist MLA Andy Allen were among those showing their support for the workers.
Steel worker and Unite shop steward Joe Passmore told staff they had achieved something “historic” as they entered the shipyard gates.
“We can see what we are going to achieve when we go through there - it's going to set the world alight,” he said.
InfraStrata said it planned to hire several hundred more workers over the next five years and CEO John Wood said Harland and Wolff was a “landmark asset” for the company.
“Its reputation as one of the finest multi-purpose fabrication facilities in Europe is testament to its highly skilled team in Belfast,” he said.