List of Seattle Mariners minor league affiliates

The Seattle Mariners farm system consists of six Minor League Baseball affiliates across the United States and in the Dominican Republic. Three teams are independently owned, while three others—the Modesto Nuts, Arizona Complex League Mariners, and Dominican Summer League Mariners—are owned by the major league club.

The Mariners have been affiliated with the Triple-A Tacoma Rainiers of the Pacific Coast League and High-A Everett AquaSox of the Northwest League since 1995, making them the longest-running affiliations in the organization among teams not owned by the Mariners. Their newest affiliates are the Double-A Arkansas Travelers of the Texas League and the Single-A Modesto Nuts of the California League, which became Mariners affiliates in 2017.

Geographically, Seattle's closest domestic affiliate is the Tacoma Rainiers, which are approximately 26 mi away. Seattle's furthest domestic affiliate is the Arkansas Travelers some 1781 mi away.

Current affiliates
The Seattle Mariners farm system consists of six minor league affiliates.

1977–1989
Prior to the 1963 season, Major League Baseball (MLB) initiated a reorganization of Minor League Baseball that resulted in a reduction from six classes to four (Triple-A, Double-A, Class A, and Rookie) in response to the general decline of the minors throughout the 1950s and early-1960s when leagues and teams folded due to shrinking attendance caused by baseball fans' preference for staying at home to watch MLB games on television. The only change made within the next 27 years was Class A being subdivided for the first time to form Class A Short Season in 1966.

1990–2020
Minor League Baseball operated with six classes from 1990 to 2020. In 1990, the Class A level was subdivided for a second time with the creation of Class A-Advanced. The Rookie level consisted of domestic and foreign circuits.

2021–present
The current structure of Minor League Baseball is the result of an overall contraction of the system beginning with the 2021 season. Class A was reduced to two levels: High-A and Low-A. Low-A was reclassified as Single-A in 2022.