The following teams, entries, and drivers have been announced to compete in the 2019 NTT IndyCar Series season.

[65] On November 10, 2018 it was announced that McLaren Racing would return to the IndyCar Series at the 2019 Indianapolis 500 with Fernando Alonso behind the wheel.

The entry will be powered by Chevrolet and piloted by Ben Hanley, who will make his IndyCar debut along with the team.

[67] On February 28, 2019, Dreyer & Reinbold Racing announced that they would once again return to run the Indy 500, retaining driver Sage Karam for the fourth consecutive year.

[25] On September 28, 2018, Chip Ganassi Racing announced that they had signed Felix Rosenqvist to drive for the team during the 2019 season.

[69] On November 14, 2018, Rahal Letterman Lanigan Racing announced that Jordan King would join the team for the Indianapolis 500.

[13] On August 8, 2019, Andretti Autosport announced that Daly would return to the team for the final race of the season at Laguna Seca.

In late June, Red Bull announced that O'Ward would be replacing Dan Ticktum at Team Mugen in Super Formula.

With this move to another series, and well-known budgetary restrictions after his crash at Indianapolis, O'Ward's rookie IndyCar season was cut short after only 8 races.

On June 4, 2019, Carlin announced that Max Chilton would not be competing in the last 4 oval events of the season at Texas, Iowa, Pocono, and Gateway.

On August 29, 2019, it was announced that Marcus Ericsson had been called up by Alfa Romeo Racing in Formula One to be on reserve driver duty at the Belgian Grand Prix.