The team joined the AL as an expansion team in 1977. Since July 1999, the Mariners' home ballpark has been Safeco Field, 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. Their mascot is the Mariner Moose.
The Mariners were created as a result of a lawsuit. In 1970, in the aftermath of the Seattle Pilots' purchase and relocation to Milwaukee as the Milwaukee Brewers by Bud Selig, the city of Seattle, King County, and the state of Washington (represented by then-state attorney general 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 NFL's expansion Seattle Seahawks in 1976. The name "Mariners" was chosen by club officials in August 1976 from over 600 names submitted by 15,000 entrants in a name-the-team contest. Ken Griffey Jr. holds six single-season batting records and an individual career record for the Mariners franchise. The Mariners played their first game on April 6, 1977, to a sold-out crowd of 57,762 at the Kingdome, losing 7–0 to the California Angels.