| 01 | van der Zande / Bourdais / Hunter-Reay | Cadillac Racing (USA) | | Cadillac | DPi-V.R | | Cadillac | DPi |
| 02 | Bamber / Lynn / Jani | Cadillac Racing (USA) | | Cadillac | DPi-V.R | | Cadillac | DPi |
| 1 | Sellers / Snow / Johansson | Paul Miller Racing (USA) | | BMW | M4 | G82 GT3 | BMW | GTD |
| 3 | Garcia / Taylor / Catsburg | Corvette Racing (USA) | | Chevrolet | Corvette C8 | .R GTD | Chevrolet | GTD Pro |
| 5 | Vautier / Westbrook / Duval | JDC Miller MotorSports (USA) | | Cadillac | DPi-V.R | | Cadillac | DPi |
| 6 | Udell / Gottsacker / de Wilde | Muehlner Motorsports America (B) | | Duqueine | D08 | | Nissan | LMP3 |
| 7 | Kvamme / Mantella / Bell | Forty7 Motorsports (USA) | | Duqueine | D08 | | Nissan | LMP3 |
| 8 | Farano / Deletraz / Pinto de Andrade | Tower Motorsport (USA) | | Oreca | 07 | | Gibson | LMP2 |
| 9 | Campbell / Jaminet / Nasr | Pfaff Motorsports (CDN) | | Porsche | 991 GT3 R | | Porsche | GTD Pro |
| 10 | Taylor / Albuquerque / Stevens | Konica Minolta Acura ARX-05 (USA) | Wayne Taylor | Acura | ARX-05 | | Acura | DPi |
| 11 | Thomas / Pierson / Bomarito | PR1 Mathiasen Motorsports (USA) | | Oreca | 07 | | Gibson | LMP2 |
| 12 | Montecalvo / Andrews / Heistand | VasserSullivan (USA) | | Lexus | RC F | GT3 | Lexus | GTD |
| 13 | Fidani / Wittmer / Kern | AWA (CDN) | Andrew Wojteczko | Duqueine | D08 | | Nissan | LMP3 |
| 14 | Hawksworth / Barnicoat / Telitz | VasserSullivan (USA) | | Lexus | RC F | GT3 | Lexus | GTD Pro |
| 16 | Hardwick / Robichon / Heylen | Wright Motorsports (USA) | | Porsche | 991 GT3 R | | Porsche | GTD |
| 18 | Merriman / Tilley / Dalziel | Era Motorsport (USA) | | Oreca | 07 | | Gibson | LMP2 |
| 20 | Andersen / Fjordbach / Scherer | High Class Racing (DK) | | Oreca | 07 | | Gibson | LMP2 |
| 21 | Mann / Pérez Companc / Vilander | AF Corse (I) | Amato Ferrari | Ferrari | 488 | GT3 | Ferrari | GTD |
| 22 | McGuire / Smith / Tappy | United Autosports (GB) | | Oreca | 07 | | Gibson | LMP2 |
| 23 | Gunn / Riberas / Martin | Heart of Racing Team (USA) | Ian James | Aston Martin | Vantage AMR | GT3 | Aston Martin | GTD Pro |
| 24 | Eng / Wittmann / Yelloly | BMW M Team RLL (USA) | | BMW | M4 | G82 GT3 | BMW | GTD Pro |
| 25 | De Phillippi / Edwards / Farfus | BMW M Team RLL (USA) | | BMW | M4 | G82 GT3 | BMW | GTD Pro |
| 27 | de Angelis / James / Gamble | Heart of Racing Team (USA) | Ian James | Aston Martin | Vantage AMR | GT3 | Aston Martin | GTD |
| 28 | de Quesada / Morad / Götz | Alegra Motorsports (USA) | | Mercedes-AMG | GT3 | Evo | Mercedes-AMG | GTD |
| 29 | van Eerd / Van Der Garde / Murry | Racing Team Nederland (NL) | | Oreca | 07 | | Gibson | LMP2 |
| 30 | Balogh / Grist / Dickerson | Jr III Racing (USA) | | Ligier | JS P320 | | Nissan | LMP3 |
| 31 | Derani / Nunez / Conway | Whelen Engineering Racing (USA) | | Cadillac | DPi-V.R | | Cadillac | DPi |
| 32 | Skeen / McAleer / Juncadella | Gilbert Korthoff Motorsports (USA) | | Mercedes-AMG | GT3 | Evo | Mercedes-AMG | GTD |
| 33 | Barbosa / Jakobsen / Willsey | Sean Creech Motorsport (USA) | | Ligier | JS P320 | | Nissan | LMP3 |
| 36 | Andretti / *Burdon / *Chaves | Andretti Autosport (USA) | Michael Andretti | Ligier | JS P320 | | Nissan | LMP3 |
| 38 | Goldburg / Lindh / Shields | Performance Tech Motorsports (USA) | | Ligier | JS P320 | | Nissan | LMP3 |
| 39 | Megennis / Lewis / Westphal | CarBahn with Peregrine Racing (USA) | | Lamborghini | Huracán | GT3 Evo | Lamborghini | GTD |
| 40 | Hanratty / Archer / Vance | FastMD Racing (USA) | | Duqueine | D08 | | Nissan | LMP3 |
| 42 | Yount / Conwright / Llarena | NTE/SSR (USA) | | Lamborghini | Huracán | GT3 Evo | Lamborghini | GTD |
| 44 | Potter / Lally / Pumpelly | Magnus Racing (USA) | John Potter | Aston Martin | Vantage AMR | GT3 | Aston Martin | GTD |
| 47 | Lacorte / Sernagiotto / Fuoco | Cetilar Racing (I) | | Ferrari | 488 | GT3 | Ferrari | GTD |
| 48 | Rockenfeller / Kobayashi / Lopez | Ally Cadillac (USA) | | Cadillac | DPi-V.R | | Cadillac | DPi |
| 52 | Keating / Jensen / Huffaker | PR1 Mathiasen Motorsports (USA) | | Oreca | 07 | | Gibson | LMP2 |
| 54 | Bennett / Braun / Kurtz | CORE Autosport (USA) | | Ligier | JS P320 | | Nissan | LMP3 |
| 57 | Ward / Ellis / Dienst | Winward Racing (USA) | | Mercedes-AMG | GT3 | Evo | Mercedes-AMG | GTD |
| 59 | Miller / Gallagher / Holton | Crucial Motorsports (USA) | | McLaren | 720S | GT3 | McLaren | GTD |
| 60 | Jarvis / Blomqvist / Vandoorne | Meyer Shank Racing W/Curb-Agajanian (USA) | Michael Shank | Acura | ARX-05 | | Acura | DPi |
| 62 | Serra / Rigon / Cheever | Risi Competizione (USA) | | Ferrari | 488 | GT3 | Ferrari | GTD Pro |
| 63 | Mapelli / Caldarelli / Bortolotti | TR3 Racing (USA) | | Lamborghini | Huracán | GT3 Evo | Lamborghini | GTD Pro |
| 66 | Simpson / Bechtolsheimer / Farnbacher | Gradient Racing (USA) | | Acura | NSX | GT3 | Acura | GTD |
| 70 | Iribe / Millroy / Pepper | Inception Racing (GB) | | McLaren | 720S | GT3 | McLaren | GTD |
| 74 | Robinson / Fraga / van Berlo | Riley Motorsports (USA) | | Ligier | JS P320 | | Nissan | LMP3 |
| 79 | MacNeil / Andlauer / Picariello | WeatherTech Racing (USA) | | Porsche | 991 GT3 R | | Porsche | GTD Pro |
| 81 | Hedman / Montoya / Montoya | DragonSpeed USA LLC (USA) | | Oreca | 07 | | Gibson | LMP2 |
| 93 | Harrison / Marcelli / Long | Racers Edge Motorsports with WTR (USA) | | Acura | NSX | GT3 Evo | Acura | GTD Pro |
| 96 | Foley / Auberlen / Dinan | Turner Motorsport (USA) | | BMW | M4 | G82 GT3 | BMW | GTD |
| 97 | MacNeil / Gounon / Engel | WeatherTech Racing (USA) | | Mercedes-AMG | GT3 | Evo | Mercedes-AMG | GTD Pro |
| 99 | Ferriol / Legge / Wilson | Team Hardpoint (USA) | | Porsche | 991 GT3 R | | Porsche | GTD |
| 99T | Ferriol / Legge / Wilson | Team Hardpoint (USA) | | Porsche | 991 GT3 R | | Porsche | GTD |