Go fish! The history behind the Mariners' Salmon Run

SEATTLE -- What started as a creative brainstorm during the thick of the pandemic has since turned into one of the Mariners’ most successful marketing ploys of this era, one that has resoundingly resonated with their fanbase.

The Salmon Run!

The fourth-inning mascot race during home games at T-Mobile Park has seen its following grow from cult-like to mainstream, from the very first sprint in 2024 to the epic one-off during the '25 postseason that drew national attention.

Born from the region’s deep connection to salmon and sustainability, the race has quietly become one of the ballpark’s most anticipated in-game traditions.

The daily event features four oversized salmon lining up along the warning track then racing toward the finish along the first-base line, after which they depart via the main concourse -- making it one of Seattle’s most on-brand spectacles.

The Salmon Run isn’t just a mascot race -- it’s a love letter to the Pacific Northwest, equal parts goofy, competitive and weird in a way only Seattle can pull off.

“Everything that we do with the Mariners, whether it's on our social channels or in-park, we try to find creative ties, either back to our region, back to baseball, back to one of our players, or back to Mariners history,” said Tyler Thompson, the team’s director of game entertainment and experiential marketing. “What we do is we try to create meaningful and authentic content, and that was super important as part of this mascot race as we were developing it.”

How it started
Thompson was the concept’s braintrust, but he’s quick to point out that going from beta to actuality “took a village” comprising many throughout the organization, as well as external vendors who built the costumes and a sponsor (Microsoft) who helps with its financing.

During the 2020 season, when fans were not in attendance, Thompson and his team began brainstorming new in-game campaigns that would be fresh when crowds were welcomed back, and the Mariners did not have a mascot race to that point.

They considered everything from Pacific Northwest rockstars to pay homage to the region’s rich music scene, former Mariners greats to bridge the organization’s past and present, and Seattle landmarks that would be easily recognizable, like the Space Needle.

But the region’s marine life wound up being the idea to which they kept coming back.

A “salmon run” is an actual expression, too. In biological terms, it’s the seasonal migration of adult salmon from the ocean (or Puget Sound, in this instance) back to the freshwater rivers and streams (which are littered throughout more inland Washington state) where they were born, for the purposes of spawning.

“And we thought, ‘Boy, we could have a lot of fun with that,’” Thompson said.

The 4 mascots
The Mariners settled on a quartet featuring four of the main species of the Pacific Northwest (all descriptions are abbreviated from the club’s website on the Salmon Run):

• King (Chinook/King salmon): Chinook are the largest and most prized salmon in the region, and can migrate as far inland to Idaho. Powerful and proud like King County, and dominant and fiery like King Félix, this mascot dons a crown and cape.
• Sockeye (Sockeye salmon): Best known for their bright red bodies and green heads during spawning, this mascot’s design is tailored as such -- paired with a fashionable flannel to play to Seattle’s grunge scene.
• Silver (Silver/Coho salmon): Smaller and more aggressive, Coho are famous for their fighting ability and dramatic spawning colors. As such, this mascot is described as “sharp as a hook” with wits, which is a nod to Seattle’s tech industry, and specifically, the race’s primary sponsor, Microsoft.
• Humpy (Pink/Humpback salmon): Nicknamed “humpies” by local fishermen for the pronounced humps that males develop while spawning, these are the region’s smallest yet most abundant salmon. And that’s precisely why he’s always the underdog for every race.

Each has a specially designed outfit embedded with Easter eggs paying homage to the Pacific Northwest -- all tailored to the fish’s features and mascots’ personalities.

Why the 4th inning?
Each game already features the seventh-inning stretch, and at T-Mobile Park, the sixth-inning Hydro Challenge on the jumbo screen. To incorporate the Salmon Run, the Mariners needed enough runway to allow the new endeavor plenty of platform.

They also wanted it to be late enough in each game to where the crowd would be mostly seated and providing undivided attention.

“The middle of the third inning is kind of when we see the lower bowl mostly full,” Thompson said. “So, the fourth felt like a natural spot.”

They actually bump it up to the third inning during the postseason because of all the extra in-game content and commercial breaks.

Humpy’s long-awaited win
And it was during the postseason where the Salmon Run really reached new heights.

During the middle of the 15th inning in Game 5 of the 2025 ALDS, Humpy finally earned his long-awaited win -- snapping an 0-for-167 run dating back to when the Salmon Run began. Then immediately after, Jorge Polanco yanked a walk-off single that won the series over Detroit, and naturally, everyone was drawing parallels to the fish’s feel-good victory and the team finally breaking through in an exhaustive marathon.

Thompson said the press requests soon were flooding in to get the story behind the story -- but he insists that Humpy’s win was not staged.

Who participates?
The Salmon Run is typically limited to employee-only participation, though there are special occasions where outsiders take part -- such as media, members of the club’s ownership group or even players’ wives.