The Mariners donned their current uniforms in 1993. White jerseys and pants are worn for most home games, while gray jerseys and pants are worn on the road. In 2011, the team brought back an alternate "Northwest Green" jersey that was previously part of the uniform set from 1994 to 1996 to be worn during Friday home games. A navy blue alternate jersey is worn for occasional road games; other variations of a navy jersey had been used as home alternates prior to the reintroduction of the Northwest Green jersey.
A navy blue cap that features a ball and compass "S" logo is paired with the home white, road gray, and navy blue jerseys. A variation of this cap with a Northwest Green brim is worn with the home alternate jersey.
In January 2015 the team announced a new alternate uniform to be worn for Sunday home games. This cream-colored "fauxback" uniform features the current logo and lettering style in a royal blue and gold color scheme, a throwback to the original team colors. Unlike the rest of the uniform set, the back of the jersey does not display the player name.The cap features the current cap logo in the throwback colors.