New Supergirl Poster! July 13, 2016 TaylorNetwork no comment on New Supergirl Poster! The CW will begin airing season one of Supergirl starting August 1 at 8 PM ET. The network will run episodes back to back leading up to the season two premiere on October 10. Check out the new poster: Share this:TwitterFacebookLinkedInPinterestRedditTumblrLike this:Like Loading...