Canamasas made his Formula racing debut in 2007 in the Spanish Formula Three Championship with the Cetea Sport team. He contested the final eight races of the season in the secondary Copa de España class for the older Dallara F300 chassis, taking a single class podium at Barcelona to finish eighth in the standings. The following season Canamasas stepped up to the main class with the same team but failed to score a point from fourteen races.
For 2009, when the series was renamed the European F3 Open Championship, Canamasas moved to the Emiliodevillota.com team. He finished the season sixth overall after taking podium results at Jarama, Jerez, and Barcelona.
In 2010, after taking part in pre-season tests with Fortec Motorsport, ISR Racing, and SG Formula, Canamasas was confirmed a week before the season opener at the new FHV Interwetten.com team alongside 2009 European F3 Open champion Bruno Méndez. He failed to score a point across all 16 races, the only full-time driver not to do so, with a best finish of fourteenth at Magny-Cours.
After off-season testing, Canamasas joined new outfit BVM-Target for 2011, racing alongside Daniel Zampieri. The season was markedly more successful: he finished eighth in the championship with a best result of third at the Hungaroring and also took a pole position for the second race at that circuit.
Canamasas entered the GP2 Series mid-season in 2012, signed by Venezuela GP Lazarus for the eighth round to replace Fabrizio Crestani. He did not score points from the ten races that season. In 2013 he ran a full campaign with EQ8 Caterham Racing and was also named Caterham F1 Team's test driver for that year. He scored just 3 points across the season.
Switching to Trident in 2014, Canamasas achieved his best GP2 result — second in the feature race and a podium third in the sprint race at Monaco. Later that season at Monza he was disqualified from the sprint race for reckless driving that caused the retirements of several other drivers, including teammate Johnny Cecotto Jr.
In 2015 Canamasas drove for three different teams — MP Motorsport (where he scored two Monaco podiums, third in the feature race and fourth in the sprint), Daiko Team Lazarus, and Hilmer Motorsport — finishing fifteenth in the combined standings. He drove for Carlin throughout the 2016 GP2 season, finishing nineteenth.
Canamasas returned to competition in 2017 with the renamed FIA Formula 2 Championship, starting with Trident before switching to Rapax after the Spielberg round. After the Budapest round, he withdrew from the series. He publicly attributed his departure to a lack of professionalism on the part of the circuit's medical staff following an incident that had endangered his father's life.