They will initially start a partial strike that will see them stop work for four hours on Friday, Sunday and Monday, then again at the end of the week, according to a strike committee established at Eulen, the company that provides the airport with agents.
Then on August 14th, the agents will go on a full, 24-hour work stoppage, said Juan Carlos Gimenez, spokesman for the committee, which was set up as none of the Eulen employees are unionised.
The 360 agents who work at the airport, a major European hub for low-cost flights, complain of a lack of personnel and overwork.
They want a stop to "16-, 14-hour days, people to be able to go to the toilet," he said.
He added many employees had taken "sick leave for psychological problems, depression... and that hinders security."
The Eulen company, however, said in a statement that it had tried to negotiate, to no avail.
It said it had attended three meetings "with the intention of negotiating and making proposals, but the strike committee either didn't show up or showed no intention of negotiating."
Even if the agents are obliged to ensure a minimum service set at 90 percent, the strike could still disrupt an airport where visitors have already regularly experienced hours-long queues at passport or security controls due to lack of staff.
While it is still behind Madrid, El Prat airport has seen passenger numbers leap 60 percent between 2009 and 2016, profiting from the huge tourist draw that is Barcelona.