Harland and Wolff shipyard has been saved from closure after being bought for £6m by a London-based energy company.
All 79 workers who opted out of taking voluntary redundancy will be kept on by Infrastrata.
The company also says it will increase the workforce by several hundred over five years.
Infrastrata has a gas storage project at Islandmagee where construction works should be take place by the end of the year with another project also planned in the future.
The shipyard went into administration in August putting 120 jobs at risk.
Workers occupied the site in east Belfast since the closure was announced, putting the pressure on the government to intervene and help save the site.
Susan Fitzgerald, from Unite the Union said: "From 29 July, when workers were faced with the imminent collapse of the yard, they were determined not only to save their own jobs, but to safeguard Northern Ireland’s skillbase going forward."
Senior Organiser of GMB, Denise Walker said: “While politicians substituted sympathy for action, workers took control of the situation and of their workplace.
"In so doing, they have ensured that Harland and Wolff will not only continue but will be in a position to expand and fulfill its potential as a linchpin of Northern Ireland’s economy."
Northern Ireland Secretary of State Julian Smith MP, said he was "delighted" with the announcement and said he believes the shipyard has a "promising future".
CEO of Infrastrata, John Wood said: "Harland and Wolff is a landmark asset and its reputation as one of the finest multi-purpose fabrication facilities in Europe is testament to its highly skilled team in Belfast."