The large group of taxis converged on the city's Ronda de Dalt intersection on Friday morning and then began to slowly drive around the intersection in small groups.
The 'slow protest' caused 8km (5 mile) traffic jams towards Llobegrat and 4km hold-ups towards Trinitat, Catalan daily La Vanguardia reported.
It has been timed to cause the maximum chaos possible with many Spaniards leaving on their annual summer holidays.
The drivers are protesting against the taxi app Uber, which they say is putting a serious dent in their business.
The Spanish region of Catalonia recently announced it would fine drivers using the popular app up to €6,000 ($8,000).
Uber is seeking open dialogue with Spanish authorities, the company told The Local recently.
"We comply with all applicable tax laws in each of the markets we operate in," the company told The Local recently, adding that they believed there was room of everyone in the transport market.
Five suspected Uber drivers face legal action after police recently found them to be looking for passengers without a taxi licence near Barcelona's El Prat airport.