Six Flags AstroWorld Home Six Flags Six Flags AstroWorld Your experiences Sign in to track your experiences. Jun 1, 1968 Six Flags AstroWorld Resort Opened Opened Jun 1, 1968 · Closed Oct 30, 2005 Six Flags AstroWorld Theme Park Opened 2002 · Closed Oct 30, 2005 WaterWorld (Houston) Water Park Oct 30, 2005 Six Flags AstroWorld Resort Closed