The second series of Attack on Titan premiered in Japan on 21 networks, including Tokyo MX and MBS, on April 1. Funimation began streaming a simulcast version on the same day, and Crunchyroll is also streaming the series. Funimation announced in December that it licensed the second anime season.
The second series premiered on Toonami on April 22.
Thanks to Gwyn Campbell for the news tip.