- New York Mets purchased Doc Medich from the Seattle Mariners on September 26, 1977.
- New York Mets selected Rick Baldwin in free agent draft on December 5, 1977.
- New York Mets sold Wayne Twitchell to the Seattle Mariners on August 19, 1979.
- New York Mets traded Gene Walter to the Seattle Mariners for Ed Nunez on July 11, 1988.
- New York Mets traded Reggie Dobie to the Seattle Mariners for Chuck Carr on November 20, 1988.
- New York Mets traded Brian Givens to the Seattle Mariners for Mario Diaz on June 19, 1990.
- Seattle Mariners signed Mackey Sasser of the New York Mets as a free agent on December 23, 1992.
- Seattle Mariners claimed Eric Gunderson of the New York Mets on waivers on August 4, 1995.
- New York Mets signed free agent Gary Thurman of the Seattle Mariners on December 20, 1995.
- New York Mets traded Blas Minor to the Seattle Mariners for Randy Vickers on June 9, 1996.
- Seattle Mariners signed Brent Mayne of the New York Mets as a free agent on January 19, 1997.
- New York Mets traded Lindsay Gulin to the Seattle Mariners for Rick Wilkins on May 12, 1998.
- New York Mets traded Butch Huskey to the Seattle Mariners for Leslie Brea on December 4, 1998.
- New York Mets traded Allen Watson to the Seattle Mariners for Justin Dunning and Mac Suzuki on June 18, 1999.
- Seattle Mariners signed John Olerud of the New York Mets as a free agent on December 7, 1999.
- New York Mets traded Rey Sanchez to the Seattle Mariners for Kenny Kelly on July 29, 2003.
- New York Mets signed free agent Mike Cameron of the Seattle Mariners on December 18, 2003.
- Seattle Mariners claimed Wilson Valdez of the New York Mets on waivers on April 1, 2005.
- New York Mets traded Aaron Heilman, Endy Chavez, Joe Smith, Jason Vargas, Maikel Cleto, Ezequiel Carrera and Mike Carp to the Seattle Mariners for Sean Green, J.J. Putz and Jeremy Reed on December 11, 2008.
- Seattle Mariners signed Kelly Shoppach of the New York Mets as a free agent on February 7, 2013.
- Seattle Mariners claimed Chasen Bradford of the New York Mets on waivers on January 19, 2018.
- New York Mets traded Jay Bruce, Anthony Swarzak, Gerson Bautista, Justin Dunn and Jarred Kelenic to the Seattle Mariners for Robinson Cano and Edwin Diaz on December 3, 2018.
- New York Mets selected Chris Mazza in free agent draft on December 13, 2018.
- Seattle Mariners signed Jose Lobaton of the New York Mets as a free agent on January 24, 2019.
- Seattle Mariners claimed Sam Haggerty of the New York Mets on waivers on January 10, 2020.
- Seattle Mariners claimed Walker Lockett of the New York Mets on waivers on September 1, 2020.
- Seattle Mariners signed Paul Sewald of the New York Mets as a free agent on January 8, 2021.
- New York Mets claimed Travis Blankenhorn on waivers from the Seattle Mariners on June 1, 2021.
- Seattle Mariners claimed Travis Jankowski of the New York Mets on waivers on August 1, 2022.
- New York Mets traded Zach Muckenhirn to the Seattle Mariners for Chris Flexen and Trevor Gott on July 3, 2023.
- New York Mets traded Rhylan Thomas to the Seattle Mariners for Ryne Stanek on July 26, 2024.
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