- Melissa Benoist as Kara Danvers/Supergirl
- Mehcad Brooks as James Olsen
- Chyler Leigh as Alex Danvers
- Jeremy Jordan as Winn Schott
- Chris Wood as Mon-El
- Katie McGrath as Lena Luthor
- David Harewood as J'onn J'onzz/Martian Manhunter and Hank Henshaw/Cyborg Superman
- Odette Annable as Reign
- Brenda Strong as Lillian Luthor/The Doctor
- Calista Flockhart as Cat Grant
- Floriana Lima as Maggie Sawyer
Thirteen-year-old Kara escaped the doomed planet Krypton with her parents' help at the same time as the infant Kal-El. Protected and raised on Earth by her foster family, the Danvers, Kara grew up in the shadow of her foster sister, Alex, and learned to conceal the phenomenal powers she shares with her famous cousin in order to keep her identity a secret. Years later, Kara was living in National City and still concealing her powers, when a plane crash threatened Alex's life and Kara took to the sky to save her. Now, Kara balances her work as a reporter for CatCo Worldwide Media with her work for the Department of Extra-Normal Operations (D.E.O.), a super-secret government organization whose mission is to keep National City and the Earth safe from sinister threats. At the D.E.O., Kara works for J'onn J'onzz, the Martian Manhunter, and alongside her foster sister, Alex, and best friend, Winn Schott. Also in Kara's life are media mogul Cat Grant, James Olsen, a photo journalist who moonlights as Guardian, a masked vigilante, Lena Luthor, and Mon-El of Daxam, whose planet was ravaged by Krypton's destruction. As Kara struggles to navigate her relationships and her burgeoning life as a reporter, her heart soars as she takes to the skies as Supergirl to fight crime.
Confirmed plot points
- There will be a four-way crossover with Arrow, The Flash and DC's Legends of Tomorrow, with Supergirl playing a much more integral role than previously.
- The "New 52" Supergirl villain known as Reign has been confirmed to be the season's "Big Bad."
|#||Episode name||Directed by||Story by||Teleplay by||Original airdate|
|1||TBA||TBA||Andrew Kreisberg||Robert Rovner & Caitlin Parrish||October 9, 2017|
- ↑ 1.0 1.1 The CW renews seven series including 'Arrow,' 'The Flash,' 'Supernatural' and 'Crazy Ex-Girlfriend' - LA Times
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 SUPERGIRL SEASON 3 SYNOPSIS - Supergirl TV
- ↑ 3.0 3.1 ‘Supergirl’: Katie McGrath Promoted To Series Regular For Season 3 - Deadline
- ↑ Supergirl Gets Odette Annable For Season 3 Villain - Kryptonsite
- ↑ 5.0 5.1 Ask Ausiello: Spoilers on Supergirl, Scorpion, Lucifer, Younger, Will & Grace, New Girl, Bloodline, Arrow and More-TVLine
- ↑ http://ew.com/tv/2017/05/26/supergirl-floriana-lima-season-3/?xid=entertainment-weekly_socialflow_twitter
- ↑ Supergirl EP Talks True Four-Way DCTV Crossover, Nixes Doppelgänger Cameos - TVLine