Season 3 (Supergirl)

The third season of premiered on October 9, 2017, on The CW and concluded on June 18, 2018. The season consisted of 23 total episodes during its run.

Synopsis
Twelve-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 Extranormal Operations (DEO), a super-secret government organization whose mission is to keep National City – and the Earth – safe from sinister threats. At the DEO, Kara works for J'onn J'onzz, the Martian Manhunter, and alongside her 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.

Main Cast

 * Melissa Benoist as Supergirl/Kara Danvers (Kara Zor-El) / Overgirl (Kara)
 * Mehcad Brooks as Guardian (James "Jimmy" Olsen) / Guardian
 * Chyler Leigh as Alex Danvers
 * Jeremy Jordan as Winn Schott
 * Katie McGrath as Lena Luthor
 * Odette Annabelle as Samantha Arias / Reign
 * Chris Wood as Mon-El
 * David Harewood as Martian Manhunter (J'onn J'onzz)

Recurring Cast

 * Floriana Lima as Maggie Sawyer
 * Erica Durance as Alura Zor-El
 * Adrian Pasdar as Morgan Edge
 * Emma Tremblay as Ruby Arias
 * Sharon Leal as Miss Martian (M'gann M'orzz)
 * Andrea Brooks as Eve Teschmacher
 * Yael Grobglas as Psi (Gayle Marsh)
 * Helen Slater as Eliza Danvers
 * Carl Lumbly as M'yrnn J'onzz
 * Chad Lowe as Thomas Coville
 * Anjali Jay as Selena
 * Curtis Lum as Demos
 * Amy Jackson as Saturn Girl (Imra Ardeen)
 * Jesse Rath as Brainiac 5 (Querl Dox)
 * Krys Marshall as Purity (Julia Freeman)

Soundtrack
On March 15, 2019, an album consisting of incidental music from the season was released digitally on Spotify and Amazon Music.