The 2021 Pacific League Climax Series (PLCS) was a set of two consecutive playoff series in Nippon Professional Baseball (NPB). The First Stage began on November 6 and the Final Stage concluded on November 12. The First Stage was a best-of-three series between the second-place Chiba Lotte Marines and the third-place Tohoku Rakuten Golden Eagles. The Final Series was a best-of-six with the Orix Buffaloes, the Pacific League champion, being awarded a one-win advantage against the Marines, the winner of the First Stage. The Buffaloes advanced to the 2021 Japan Series to compete against the Tokyo Yakult Swallows, the 2021 Central League Climax Series winner.