Qualifying Groups for Sonoma
Here are the qualifying groups for the final Firestone Fast Six qualifying session of the 2018 season.
| No. | Group 1 | No. | Group 2 |
| 12 | Power, Will | 9 | Dixon, Scott |
| 27 | Rossi, Alexander | 28 | Hunter-Reay, Ryan |
| 22 | Pagenaud, Simon | 1 | Newgarden, Josef |
| 30 | Sato, Takuma | 26 | Veach, Zach |
| 98 | Andretti, Marco | 39 | Ferrucci, Santino |
| 15 | Rahal, Graham | 10 | Jones Ed |
| 21 | Pigot, Spencer | 23 | Kimball, Charlie |
| 5 | Hinchliffe, James | 60 | Harvey, Jack |
| 19 | Fittipaldi, Pietro | 20 | King, Jordan |
| 59 | Chilton, Max | 6 | Munoz, Carlos |
| 88 | Herta, Colton | 8 | O'Ward, Patricio |
| 4 | Leist, Matheus | 14 | Kanaan, Tony |
| – | – | 18 | Bourdais, Sebastien |