The Seattle Mariners are an American professional baseball team based in Seattle. The Mariners compete in Major League Baseball (MLB) as a member club of the American League (AL) West Division. The team joined the American League as an expansion team in 1977, playing their home games in the Kingdome. Since July 1999, the Mariners' home ballpark has been T-Mobile Park, located in the SoDo neighborhood of Seattle. The "Mariners" name originates from the prominence of marine culture in the city of Seattle. They are nicknamed the M's, a title featured in their primary logo from 1987 to 1992. They adopted their current team colors – navy blue, northwest green (teal), and silver – prior to the 1993 season, after having been royal blue and gold since the team's inception; the original colors continue to be used in alternate uniforms. Their mascot is the Mariner Moose. The Mariners did not field a winning team until 1991, and further success eluded them until the late 90s, the most successful period in franchise history. Led by Hall of Fame players Edgar Martínez, Ken Griffey Jr., and Randy Johnson, the Mariners clinched their first playoff berth in 1995 when they won their first division championship and defeated the New York Yankees in the ALDS. Martínez's walk-off double in Game 5 drove Griffey in from first base to win the game in the 11th inning, clinched a series win for the Mariners, served as a powerful impetus to preserve baseball in Seattle, and has since become an iconic moment in team history. They would later win their second division title in 1997. After Griffey, Johnson, and Alex Rodriguez all left the team, the Mariners, bolstered by the signing of Ichiro Suzuki, won 116 games in 2001, which set the American League record for most wins in a single season and tied the 1906 Chicago Cubs for the Major League record for most wins in a single season. The team would not make the postseason again until 2022, which was the longest active drought in the four major North American sports. As of 2024, the franchise has finished with a losing record in 30 of 48 seasons. The Mariners are the only active MLB franchise never to have appeared in the World Series, currently holding the longest active World Series appearance drought in MLB.

T-Mobile Park

The Washington Nationals are a professional baseball team based in Washington, D.C. The Nationals compete in Major League Baseball (MLB) as a member club of the National League (NL) East division. From 2005 to 2007, the team played in RFK Stadium; since 2008 their home stadium has been Nationals Park on South Capitol Street in Southeast D.C., near the Anacostia River.