The Mariners were created as a result of a lawsuit. In , after
Bud Selig bought the
Seattle Pilots and moved them to Milwaukee to become the
Milwaukee Brewers, the city of
Seattle,
King County, and the state of
Washington (represented by then-state Attorney General and future U.S. Senator
Slade Gorton) sued the American League for breach of contract. Confident that Major League Baseball would return to Seattle within a few years, King County built the multi-purpose Kingdome, which would become home to the National Football League's expansion
Seattle Seahawks in
1976. The name "Mariners" was chosen by club officials in August 1976 from more than 600 names submitted by 15,000 entrants in a "name the team" contest. The name was submitted by Roger Szmodis of
Bellevue, Washington. When the Mariners attempted to reach Szmodis about the prize he had won, they were unsuccessful—initially and ultimately. holds six single-season batting records and an individual career record for the Mariners franchise. The first home run in team history was hit on April 10, 1977, by designated hitter
Juan Bernhardt. That year, pitcher
Diego Seguí, in his last major league season, became the only player to play for both the Pilots and the Mariners. The Mariners finished with a 64–98 record, matching the 1969 Pilots' record. The team avoided finishing in last place in the AL West by half a game. The Mariners would not post a winning record or finish above 4th place in any of their first 14 seasons. In 1979, Seattle hosted the
50th Major League Baseball All-Star Game. After the 1981 season, the Mariners were sold to California businessman
George Argyros, who in turn sold the team in 1989 to a group led by Indianapolis-based
Jeff Smulyan, who owned radio and television stations, for $76 million. Smulyan proposed moving the team to
Tampa, Florida or another market in 1992 before he put the team up for sale.
Nintendo of America bought the team in 1992; Nintendo CEO
Hiroshi Yamauchi, who held a 49 percent share of the franchise, had never been to a baseball game but sought to thank the city for its role in the company's success. Before the 1993 season, the Mariners hired manager
Lou Piniella, who had led the
Cincinnati Reds to victory in the
1990 World Series. Mariners fans embraced Piniella, and he would helm the team from through , winning two American League
Manager of the Year Awards during his tenure. (Piniella was selected by the Pilots in the
1968 expansion draft but did not play for Seattle, being traded in April 1969 to the
Kansas City Royals, where he earned AL
Rookie of the Year honors that year.) The Mariners first won the AL West and made the playoffs in 1995, despite star outfielder
Ken Griffey Jr. missing much of the season after breaking his wrist crashing into the center field wall. The team defeated the California Angels in a one-game playoff to win the division. The Mariners returned to the playoffs in 1997 and 2000. The Mariners finished with a record of 116–46, leading all of Major League Baseball in winning percentage for the duration of the season and easily winning the American League West division title. In doing so, the team broke the
1998 New York Yankees' American League single-season record of 114 wins and matched the all-time MLB single-season record for wins set by the
Chicago Cubs. At the end of the season,
Ichiro Suzuki won the AL
MVP, AL
Rookie of the Year, and one of three outfield
Gold Glove Awards, becoming the first player since the
Fred Lynn in 1975 to win all three in the same season. The Mariners advanced through the postseason but lost to the
Yankees in the
2001 ALCS. It would be the team's last playoff appearance until 2022. The Mariners had a 93-win season in but failed to make the postseason. Manager Lou Piniella was traded to the
Tampa Bay Rays during the offseason. The team repeated with 93 wins in 2003 and also did not qualify for the playoffs. Weeks later, on November 18, the team named
Oakland Athletics bench coach
Don Wakamatsu as its new manager. The off-season also saw a litany of roster moves, headlined by a 12-player, 3-team trade that sent All-Star closer
J. J. Putz to the
New York Mets and brought 5 players, including prospect
Mike Carp and outfielder
Endy Chávez from New York and outfielder
Franklin Gutiérrez from the
Cleveland Indians, to Seattle. Many of the moves, like the free-agent signing of
Mike Sweeney, were made in part with the hope of squelching the clubhouse infighting that plagued the Mariners in 2008. It also saw the return of Seattle favorite Griffey Jr. The 2009–10 offseason was highlighted by the trade for 2008 AL
Cy Young Award winner
Cliff Lee from the
Philadelphia Phillies, the signing of third baseman
Chone Figgins, and the contract extension of star pitcher
Félix Hernández. (1977–June 1999) Griffey Jr. announced his retirement on June 2, 2010, after 22 MLB seasons. After its busy offseason and high expectations, the team flopped in 2010, finishing with the worst record in the American League. The Mariners fired
Wakamatsu along with several coaches on August 9, 2010.
Daren Brown, the manager of the Triple-A affiliate
Tacoma Rainiers, took over as interim manager.
Dave Niehaus, the Mariners' play-by-play announcer since the team's inception, died of a
heart attack on November 10, 2010, at the age of 75. In memory of Niehaus, Seattle rapper
Macklemore wrote a tribute song called "My Oh My" in December 2010. He performed the song at the Mariners'
Opening Day game on April 8, . The Mariners hired former Cleveland manager
Eric Wedge as their new manager on October 19, 2010. On April 21, 2012,
Philip Humber of the
Chicago White Sox threw the
third perfect game in White Sox history against the Mariners in Seattle. It was the 21st
perfect game in
MLB history. Mariners starter
Kevin Millwood and five relievers combined to throw the tenth combined no-hitter in MLB history, the first in Mariners history, on June 8. The six pitchers used in a no-hitter tied a major league record, first set by the
Houston Astros in 2003.
Félix Hernández pitched the
first perfect game in team history, shutting down the
Tampa Bay Rays 1–0 at
Safeco Field on August 15. It was the 23rd perfect game in Major League Baseball history. The Mariners became the first team in Major League Baseball to be involved in two perfect games in one season. Zduriencik was fired on August 28, 2015.
Jerry Dipoto, a former general manager of the
Los Angeles Angels of Anaheim, was hired as the Mariners' new general manager one month later. On October 9, manager
Lloyd McClendon was fired.
Scott Servais was named the new Mariners' manager on October 23.
Nintendo announced on April 27, 2016, that it would sell its controlling stake in the Mariners to First Avenue Entertainment
limited partnership, led by
John W. Stanton. Nintendo retained a 10 percent ownership share of the team after the sale was completed in August 2016. The franchise was valued at $1.4 billion at the time and included
Root Sports Northwest, the team's regional television network. The Stanton/Dipoto/Servais era was characterized by two competitive phases. In the first phase, the organization tried to contend for a championship with the existing core of
Robinson Cano,
Félix Hernández,
Nelson Cruz, and
Kyle Seager. The team came close but ultimately missed the playoffs. Following the 2018 season, the organization pivoted to a rebuild, trading several players for prospects. Following a fallow period of 2019–20, the team returned to contention in 2021, winning 90 games but falling short of the playoffs. In 2022, with a new core including
Julio Rodríguez,
J. P. Crawford,
Cal Raleigh,
Luis Castillo,
George Kirby, and
Logan Gilbert, the team reached the postseason for the first time since 2001. This broke what was at the time the longest playoff drought of any team in the "Big Four" North American sports. Rodríguez also won the American League Rookie of the Year Award. In 2023, the team won 88 games but finished one game out of a playoff spot. In August 2024, Servais was fired after blowing a 10 game lead in the AL West over the
Houston Astros and having the team fall back to .500. Servais was replaced by the team's former catcher
Dan Wilson as manager. The team again missed the playoffs by one game. In 2025, the Mariners won their first AL West title since 2001. In the
2025 playoffs, they defeated the
Tigers in the
ALDS in 5 games and had a 2-0
ALCS lead against the
Blue Jays until they ultimately blew a 3-1 lead in Game 7. This was the first time the franchise ever played in a Game 7, also meaning this is the closest they have ever been to a World Series appearance. ==Uniforms==