The January 2017 edition of Bessatsu Shounen magazine has made huge announcements for the second season of Hajime Isayama’s Attack on Titan, including when it will premiere, which will be on April 2017.
The stage play is slated for summer 2017.
The announcement also revealed that a Blu-ray/DVD box set is slated to be released on March 2017, while a stage play is also planned, and it is called Attack on Titan: Live Impact.
This means that it will premiere in spring, the same season where the first anime was shown.