Barba began his racing career in 2003 in the Spanish Formula Junior 1600 series, taking a single podium and two pole positions to finish the year in 12th place.

The following year, he stepped up to the championship full-time with Campos Racing, competing in the Copa de España class for older generation Dallara chassis.

During this period, he secured 14 podium places, including four race wins, and finished as runner–up to teammate Máximo Cortés in the 2007 season, losing out on the title by just four points.

[4] In September 2006, Barba made his debut in the Formula Renault 3.5 Series at Donington Park, driving for Jenzer Motorsport alongside his older brother Álvaro.

In July 2008, Barba teamed up with his brother Álvaro to race a Mosler MT900R in the International GT Open event held at the newly constructed Valencia Street Circuit.