The 2020 Seattle Mariners season was the 44th season in franchise history. The Mariners played their 21st full season (22nd overall) at T-Mobile Park, their home ballpark. The Mariners entered this season with the longest active playoff drought in the four major North American professional sports leagues, attempting to make their first postseason since 2001. They also entered this season as the only team to not win a league pennant.