Construction workers who downed tools last month at a liquefied natural gas (LNG) site at Milford Haven were returning to work on Wednesday.
The dispute began when workers walked out on 10 May
Talks between their union and company managers mean they will be reinstated with full continuity of service.
Around 250 people, mainly welders, steel erectors and labourers, left the site over asbestos concerns.
About 100 who refused to return were sacked and many had been picketing the plant at South Hook.
The company, South Hook LNG, had always said that although "small quantities" of asbestos-cement pipe were being removed from the site it posed no health or safety risk.
Over a week after their original walk out, the Health and Safety Executive also gave reassurance and the men voted to go back to work.
But their employer, Chicago Bridge and Iron, believed they had been in breach of their contracts and told them they were no longer needed.
Since then, the men have been picketing every day outside the gates to get their jobs back.
Almost a fortnight later, they are finally being allowed to return to work.
However, they have been told they will not be able to claim their loss of earnings, which now adds up to almost a month's pay.