Robin started karting in places around Belgium and France, competing in a multitude of karting championships around there. He started karting professionally in 2004, winning Open Belgian Championship Cadet’s category. Frijns had equally more success: winning the French Junior Championship; coming second in Grand Prix Karting FFSA Junior category, Open Belgian Championship in ICA Junior, Belgian Championship ICA Junior and French Championship KF2; third in both KF2 championships in South Garda Winter Cup and CIK-FIA European Championship.
Robin made his single seater debut in Formula BMW Europe in 2009, competing with Josef Kaufmann Racing. In his debut season, he stood on the podium 6 times with a win in Silverstone, meaning he was the highest placed rookie and 3rd in the main standings with 265 points.
For the following year, he was retained by Josef Kaufmann Racing for 2010, this time competing in Formula BMW Europe and a round of Formula Renault 2.0 Northern European Cup. His second season in Formula BMW finished in 1st with 6 wins and 13 podiums, finishing 11 points ahead of Jack Harvey. In the single round of Formula Renault 2.0, he finished 2nd, 5th and 1st in each of the races respectively. With 70 points under his name, he finished in 14th.
Once again, Frijns raced with Josef Kaufmann Racing again, competing solely in Formula Renault 2.0, but this time in Eurocup and Northern European Cup. With 5 wins and 9 podiums in 14 races, he ultimately finished in 1st ahead of current Formula 1 driver, Carlos Sainz Jr. In NEC, he missed three rounds competing in the first 4 and the 6th. Despite this, he finished in 4th position behind Stoffel Vandoorne, earning a win and 7 podiums.
For the 2012 season, he raced solely in Formula Renault 3.5, joining Carlos Huertas in Fortec Motorsports. Robin finished ahead of French driver Jules Bianchi, winning the championship in his rookie season. With 8 podiums with 3 being wins, he scored 189 points.
2013 provided the end of his single seaters besides Formula E. He competed with Hilmer Motorsport in the GP2 Series. Even though he only completed 6 rounds, he managed to achieve a win and 2 podiums out of the 12 races he competed in. Frijns finished in 15th with 47 points. Also during 2013, he became Sauber F1 Team’s test driver.
He once again was a Formula 1 test driver in 2014, this time for Caterham Racing. He did not compete in any series besides testing.
2015 started his touring cars debut in Blancpain. Frijns competed in the sprint series, endurance series and GT series. Despite being his debut, he raced in the pro class for both the sprint and endurance series. In all three series, Robin competed with Belgian Audi Club Team WRT. He finished in 2nd in sprint, 6th in endurance and 1st in GT.
Frijns was kept by Belgian Audi Club Team WRT for the 2016 season, competing in Blancpain Sprint series and Endurance series. In the Sprint championship, he competed in 8 races, winning a race and on the podium another time. Here he finished in 10th with 33 points. In the endurance series, he was only able to claim 4 points meaning he finished in 42nd. Along with Blancpain, Robin also competed in a round of ADAC GT Masters driving with APR Motorsport. Frijns competed in the Lausitzring round, though was unable to claim any points therefore he was unclassified as he didn’t gain any points. Along with these, he competed in the Intercontinental GT series, competing in the Spa round only. Despite this, he finished 1st with Audi, therefore finishing in 7th.
For 2017, he joined Team WRT for Blancpain Sprint, Endurance and FIA GT World Cup. With Stuart Leonard, Robin finished in 1st for the sprint series, winning 2 races out of the 8. Having only completed 2 races in the endurance series, he finished in 13th, though he did finish 6th and 2nd. Along with this, he competed in the GT World Cup at Macau, driving Audi Sport Team WRT. Frijns finished 4th in the qualifying race after a large pile of cars were stuck in Police Bend corner. For the main race, he finished in 2nd behind fellow Formula E driver, Edoardo Mortara. Once again, he competed in the Intercontinental GT series with Audi. Having retired in the first round, not competing in the second and coming 6th in the last, he finished in 12th with 8 points behind Jeroen Bleekemolen.
For the 3rd year, Frijns competed in Blancpain Sprint and Endurance Cup, again competing for Belgian Audi Club Team WRT and Audi Sport Team WRT for a race of Endurance. He finished 15th with 13 points and 29th with 14 points respectively. Competing again with Audi, Robin drove in the Intercontinental GT Series. He finished 1st in Bathurst, 4th at Spa, didn’t partake in Suzuka and 2nd at Laguna Seca. With 2 podiums and a win under his name, he finished the season with 55 points, coming joint 5th with Dries Vanthoor. For the second year, he competed in the FIA GT World Cup, competing with Audi Sport Team WRT Speedstar. He finished 6th in the qualifying race and 5th in the main race. Frijns competed in a round of WeatherTech SportsCar Championship with Jackie Chan DCR JOTA, where he finished 11th in the race and 55th in the standings.
In 2019, Robin once again competed in Blancpain Endurance, this time with Audi Sport Team WRT. Competing in the Spa round, he finished in 23rd (though got 9th in the 6th hour and 8th in the 12th hour meaning they earned 3 points). With Nico Müller and René Rast, they finished 32nd in the standings. Frijns also competed in the Intercontinental GT Series, with Audi. He competed only in the 24 hours of Spa round, but him and his team were unable to claim any points therefore finishing unclassified in the final standings. Robin made his Deutsche Tourwagen Masters (DTM) debut with Audi Sport Team Abt Sportsline, driving with fellow Audi member and Formula E driver Nico Müller. He claimed 5 podiums out of the 18 races he competed in, earning 157 points therefore finishing in 5th.
For the 2020 season, he will be competing again with Audi Sport Team Abt Sportsline for the DTM championship, with the season commencing in Zolder.
Robin started his Formula E career with in 2015 with Amlin Andretti, driving alongside Swiss driver Simona de Silvestro. Claiming a podium, he finished in 12th with 45 points and brought Andretti to 7th in the standings.
The following year, Frijns was retained by Andretti, this time joined by Portuguese driver António Félix da Costa. This time, he finished in 13th with 24 points. With António’s points, the team finished with 34 points and Andretti once again finishing in 7th.
He took a season out, driving elsewhere, until the 2018-2019 season. He was signed onto Envision Virgin Racing with Sam Bird, competing in their outfit as the number 4. Robin achieved 4 podiums with 2 wins inclusive in Paris and New York City race 2. This time he accumulated 106 points meaning Robin finished 4th in the standings ahead of Mitch Evans.