Announced in season 2 finale on Saturday

The second anime season based on Hajime Isayama's Attack on Titan manga ended on Saturday, and the season finale announced that the third season will premiere in 2018.

The second season 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 English dub of the second season premiered on Adult Swim's Toonami in April, and then on Funimation's streaming service a day later.

Source: Mainichi Shimbun's Mantan Web