2019 saw Olli contest Formula Regional European Championship, teaming up once again with Prema Powerteam.
The championship took place over eight rounds, racing at Paul Ricard, Vallelunga, Red Bull Ring, Imola, Mugello and Monza, whilst also making his racing debut at Hungaroring and Catalunya.
Finishing the season in 5th place, Olli scored a win at Imola and 5 podium finishes, gracing the podium 3 times in only his first time racing at Hungaroring.