Thor 3 is now officially known as Thor: Ragnarok, and is confirmed to hit theaters on July 28, 2017:
“This is a very important movie for us in Phase 3,” said Marvel’s Kevin Feige. “We plan on taking Thor to another level. It picks up where we leave Thor in ‘Avengers: Age of Ultron’ and impacts everything that comes after.”
Chris Hemsworth is confirmed to return as the Mightiest Avenger – for now no other cast details have been confirmed.
On stage at Marvel’s event, Feige confirmed that in this context Ragnarok means “The end of all things.” The movie was also called out as the “key film” of Phase Three, and that it starts right after Avengers: Age of Ultron.