It was announced at the Shingeki Festival's Reading and Live event that Attack on Titan Season 2 will be premiering in the Spring of 2017.
Isayama also wrote a letter acknowledging the long wait for the sequel but hopes the fans still look forward to it. A key visual of Eren, Mikasa, Armin, and the Armored and Colossal Titans was shown to the attendees.
Also Masashi Koizuka will be the new Director as Tetsuro Araki is serving as the chief director
An official website for the season has also been launched: http://shingeki.tv/season2/