Almost 4,000 tonnes of stone will be used in the coming weeks for coastal protection works at Aberavon beach.
Heavy machinery will be used to lay large boulders at the lower promenade wall at the Blue Flag winning sands.
Contractors said there may be some disruption as disabled access is also improved along with other works, expected to last around 10 weeks.
Neath Port Talbot Council has spent almost £4m during the last decade to regenerate the area.
It said signs would be erected to advise members of the public on what areas are out of bounds.
Council leader Ali Thomas said: "Aberavon beach is one of our main assets that continues to be a key tourist attraction.
"The protection works that are being carried out will ensure that the promenade will continue to be used by hundreds of people every day."
Aberavon was awarded the Blue Flag for the first time in the history of the awards two years ago.