The second season of World Trigger hasn’t even aired yet (premieres January 9) and, still, a third season was announced at Jump Festa ’21. During this event, it was also announced that the second season will only be airing for one cours… meaning it will either be 12 or 13 episodes. This is a much smaller number of episodes than the anime’s first season which ran for 73 episodes.
Right now, we do not know when the third season is slated to air and how many episodes there will be. The first season ended due to the fact that the anime had caught up to the manga. The smaller number of episodes could be due to pacing the adaptation to avoid that problem once again.
You can see the original announcement in the Tweet below (break out Google Translate)
ジャンプフェスタ #ワールドトリガー ステージ終了しました!ご視聴いただいた皆さま、ありがとうございました!🙏
ステージで発表されましたが、分割2クールということで、3rdシーズンの製作が決定しました!
1月からの2ndシーズンは1クール、3rdシーズンの放送時期は後日発表予定です。お楽しみに! pic.twitter.com/utAGsus8Vd— ワールドトリガー アニメ公式 (@Anime_W_Trigger) December 19, 2020