William Antonio Karlsson (born 18 October 2005) is a Swedish racing driver who competes in the LMP3 class of the Le Mans Cup for Inter Europol Competition.
Personal life Karlsson is the son of Nicklas Karlsson, a former racing driver who founded NIKA Racing in 2006.
Career Towards the end of 2019, Karlsson made his single-seater debut in the Aquila Synergy Cup Sweden. Moving to his family's NIKA Racing to race in Formula Nordic the following year, Karlsson took his only win of the season at Mantorp Park en route to fifth in points. Remaining in the series for 2021, Karlsson took seven wins and five other podiums to secure the series title. In 2022, Karlsson joined Renauer Motorsport to compete in the ACCR Formula 4 Trophy. However, he later joined BVM Racing to compete in the Italian F4 Championship, taking his only points of the season in race three at the Red Bull Ring.
The following year, Karlsson joined Drivex to compete in the newly-formed Eurocup-3. Competing in the first three rounds, Karlsson scored his only points of the season at Aragón, finishing eighth and ninth in the two races. After a one-off appearance in Porsche Sprint Challenge Scandinavia, Karlsson joined KIC Motorsport to compete in select rounds of the Formula Regional European Championship, taking a best result of 20th at Monza.
After spending 2024 on the sidelines, Karlsson returned to single-seaters in early 2025 with Renauer Motorsport at the second Red Bull Ring round of F4 CEZ, finishing second twice. During 2025, Karlsson made his endurance prototype debut, racing for Inter Europol Competition at the Road to Le Mans in LMP3 Pro-Am, finishing fifth in both races. In 2026, Karlsson returned to Inter Europol and the Le Mans Cup to compete in his rookie season in the LMP3 class alongside Christian Dannemand Jørgensen.
Karting record Karting career summary SeasonSeriesTeamPosition 2014MKR Series Sweden — CadetKatrineholms MK2015MKR Series Sweden — Formula Micro6thGöteborgs Stora Pris — Micro5thJuniorfestivalen — Micro2ndKristianstad KK Grande Finale — Micro1st2016MKR Series Sweden — Junior 607thSwedish Kart Championship — Junior 60NIKA Racing10thGöteborgs Stora Pris — Junior 605thWSK Final Cup — 60 MiniBirel ART RacingNC2017WSK Champions Cup — 60 MiniBirel ART RacingNCWSK Super Master Series — 60 Mini88thSouth Garda Winter Cup — 60 MiniNCMKR Series Sweden — Junior 60KAK Motorsport4thSwedish Kart Championship — Junior 6014thRaket Cup Sweden — Mini38thBNL Golden Trophy — Junior Max31st2018Andrea Margutti Trophy — OK-JJP Racing26thSwedish Championship — OK-J23rdSverigeCupen — OK-J7thDeutsche Kart-Meisterschaft — OK-JJP RacingNCKarting World Championship — OK-JNC2019South Garda Winter Cup — OK-JWard Racing28thWSK Super Master Series — OK-J77thSwedish Championship — OK-J9thKarting European Championship — OK-JNika International99thDeutsche Kart-Meisterschaft — OK-J15thSources:
Racing record Racing career summary SeasonSeriesTeamRacesWinsPolesF/LapsPodiumsPointsPosition 2019 Aquila Synergy Cup Sweden 6 0 0 0 0 107 11th 2020 Formula Nordic NIKA Racing 16 1 0 0 8 199 5th 2021 Formula Nordic NIKA Racing 15 7 6 5 12 3051st 2022 Italian F4 Championship BVM Racing 17 0 0 0 0 1 26th2023 Eurocup-3 Drivex 6 0 0 0 0 6 17th Porsche Sprint Challenge Scandinavia Porsche Experience Racing 2 0 0 0 0 16.5 18th Formula Regional European Championship KIC Motorsport 4 0 0 0 0 0 40th2025 Formula 4 CEZ Championship Renauer Motorsport 3 0 0 0 2 42 14th Le Mans Cup – LMP3 Pro-Am Inter Europol Competition 2 0 0 0 0 12 21st 2026 Le Mans Cup – LMP3 Inter Europol Competition Sources:
Complete Italian F4 Championship results (key) (Races in bold indicate pole position) (Races in italics indicate fastest lap) Year Team 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 DC Points 2022 BVM RacingIMO1IMO2IMO3MIS1MIS2MIS3SPA1SPA2SPA3VLL1VLL2VLL3RBR1RBR2RBR3RBR4MNZ1MNZ2MNZ3MUG1MUG2MUG3 26th 1
Complete Eurocup-3 results (key) (Races in bold indicate pole position) (Races in italics indicate fastest lap) Year Team 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 DC Points2023DrivexSPA1SPA2ARA1ARA2MNZ1MNZ2ZAN1ZAN2JER1JER2EST1EST2CRT1CRT2CAT1CAT2 17th 6
Complete Formula Regional European Championship results (key) (Races in bold indicate pole position) (Races in italics indicate fastest lap) Year Team 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 DC Points 2023 KIC Motorsport IMO1 IMO2 CAT1 CAT2 HUN1 HUN2 SPA1 SPA2 MUG1 MUG2 LEC1 LEC2 RBR1 RBR2 MNZ1MNZ2 ZAN1 ZAN2 HOC1 HOC2 40th 0
Complete Formula 4 CEZ Championship results (key) (Races in bold indicate pole position) (Races in italics indicate fastest lap) YearTeam123456789101112131415161718DCPoints 2025 Renauer MotorsportRBR11RBR12RBR13RBR21RBR22RBR23SAL1SAL2SAL3MOS1MOS2MOS3SVK1SVK2SVK3BRN1BRN2BRN3 14th 42
Complete Le Mans Cup results (key) (Races in bold indicate pole position; results in italics indicate fastest lap) YearEntrantClassChassis1234567RankPoints 2025 Inter Europol Competition LMP3 Pro-Am Ligier JS P325 BAR LEC LMS1 LMS2 SPA SIL POR 21st 12 2026 Inter Europol Competition LMP3 Ligier JS P325 CAT LEC LMS SPA SIL ALG 22nd* 0*
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