Mariners Roster & Staff
Transactions
| Date | Transaction |
| 01/30/25 | Seattle Mariners invited non-roster C Josh Caron to spring training. |
| 01/30/25 | Seattle Mariners invited non-roster SS Cole Young to spring training. |
| 01/30/25 | Seattle Mariners signed free agent RHP Shintaro Fujinami to a minor league contract and invited him to spring training. |
| 01/30/25 | Seattle Mariners invited non-roster 2B Brock Rodden to spring training. |
| 01/30/25 | Seattle Mariners invited non-roster RHP Tyler Cleveland to spring training. |
| 01/30/25 | Seattle Mariners invited non-roster C Harry Ford to spring training. |
| 01/30/25 | Seattle Mariners invited non-roster 3B Nick Dunn to spring training. |
| 01/30/25 | Seattle Mariners invited non-roster 3B Ben Williamson to spring training. |
| 01/30/25 | Seattle Mariners invited non-roster LF Rhylan Thomas to spring training. |
| 01/30/25 | Seattle Mariners invited non-roster 2B Samad Taylor to spring training. |
| 01/30/25 | Seattle Mariners invited non-roster LF Spencer Packard to spring training. |
| 01/30/25 | RHP Luis F. Castillo roster status changed by Seattle Mariners. |
| 01/30/25 | Seattle Mariners invited non-roster SS Colt Emerson to spring training. |
| 01/30/25 | Seattle Mariners invited non-roster LHP Peyton Alford to spring training. |
| 01/30/25 | Seattle Mariners signed free agent RHP Neftalí Feliz to a minor league contract and invited him to spring training. |
| 01/30/25 | Seattle Mariners invited non-roster RHP Logan Evans to spring training. |
| 01/30/25 | Seattle Mariners invited non-roster RHP Hunter Cranton to spring training. |
| 01/30/25 | Seattle Mariners invited non-roster RF Lazaro Montes to spring training. |
| 01/30/25 | Seattle Mariners invited non-roster SS Michael Arroyo to spring training. |
| 01/30/25 | Seattle Mariners invited non-roster LHP Brandyn Garcia to spring training. |
| 01/30/25 | Seattle Mariners signed free agent RHP Luis Castillo to a minor league contract and invited him to spring training. |
| 01/30/25 | Seattle Mariners invited non-roster C Connor Charping to spring training. |
| 01/29/25 | Seattle Mariners signed free agent OF Diago Machado to a minor league contract. |
| 01/29/25 | Seattle Mariners signed free agent LHP Adam Seminaris to a minor league contract. |
| 01/29/25 | Seattle Mariners sent LHP Tyler Jay outright to Tacoma Rainiers. |
| 01/28/25 | Seattle Mariners signed free agent SS Nathan Rose to a minor league contract. |
| 01/22/25 | Seattle Mariners signed free agent C Julio E. Rodriguez to a minor league contract. |
| 01/21/25 | Seattle Mariners signed free agent 2B Po-Chun Lin to a minor league contract. |
| 01/21/25 | Seattle Mariners designated LHP Tyler Jay for assignment. |
| 01/21/25 | Athletics traded RHP Will Klein to Seattle Mariners for Other Considerations. |
| 01/21/25 | Seattle Mariners sent 2B Samad Taylor outright to Tacoma Rainiers. |
| 01/17/25 | Seattle Mariners designated 2B Samad Taylor for assignment. |
| 01/17/25 | Seattle Mariners signed free agent RHP Maximo Rodriguez to a minor league contract. |
| 01/17/25 | Seattle Mariners sent C Nick Raposo outright to Tacoma Rainiers. |
| 01/16/25 | Seattle Mariners signed free agent RHP Alan Carpinteiro to a minor league contract. |
| 01/16/25 | Seattle Mariners sent LHP Austin Kitchen outright to Tacoma Rainiers. |
| 01/15/25 | Seattle Mariners signed free agent RHP Christopher Quiroz to a minor league contract. |
| 01/15/25 | Seattle Mariners signed free agent RHP Henry Alcantara to a minor league contract. |
| 01/15/25 | Seattle Mariners designated 2B Samad Taylor for assignment. |
| 01/15/25 | Seattle Mariners signed free agent RHP Randal Munoz to a minor league contract. |
| 01/15/25 | Seattle Mariners signed free agent OF Maikol Rodriguez to a minor league contract. |
| 01/15/25 | Seattle Mariners signed free agent OF Elias Perez to a minor league contract. |
| 01/15/25 | Seattle Mariners signed free agent RHP Cesar Farias to a minor league contract. |
| 01/15/25 | Seattle Mariners signed free agent SS Kendry Martínez to a minor league contract. |
| 01/15/25 | Seattle Mariners signed free agent C Beau Taylor to a minor league contract. |
| 01/15/25 | Seattle Mariners signed free agent RHP Ismanuel Pina to a minor league contract. |
| 01/15/25 | Seattle Mariners signed free agent RHP Wisler Infante to a minor league contract. |
| 01/15/25 | Seattle Mariners signed free agent C Manuel Almeida to a minor league contract. |
| 01/15/25 | Seattle Mariners signed free agent C Manuel Almeida to a minor league contract. |
| 01/15/25 | Seattle Mariners signed free agent RHP Darwin Ramos to a minor league contract. |
| 01/15/25 | Seattle Mariners signed free agent OF Yorger Bautista to a minor league contract. |
| 01/15/25 | Baltimore Orioles traded C Blake Hunt to Seattle Mariners for cash. |
| 01/14/25 | Seattle Mariners signed free agent 2B Jack López to a minor league contract. |
| 01/14/25 | Seattle Mariners designated C Nick Raposo for assignment. |
| 01/14/25 | Chicago Cubs traded SS Miles Mastrobuoni to Seattle Mariners for cash. |
| 01/13/25 | Seattle Mariners designated LHP Austin Kitchen for assignment. |
| 01/13/25 | Seattle Mariners signed free agent 3B Donovan Solano. |
| 01/10/25 | Seattle Mariners signed free agent C Freuddy Batista to a minor league contract. |
| 01/09/25 | Seattle Mariners signed free agent OF Yoyner Fajardo to a minor league contract. |
| 01/09/25 | Seattle Mariners claimed LHP Tyler Jay off waivers from Milwaukee Brewers. |
| 01/08/25 | Seattle Mariners claimed RHP Hagen Danner off waivers from Toronto Blue Jays. |
| 01/03/25 | Seattle Mariners signed free agent LHP Josh Fleming to a minor league contract. |
| 01/03/25 | LHP Josh Fleming roster status changed by Seattle Mariners. |
| 01/02/25 | Seattle Mariners signed free agent RHP Dylan File to a minor league contract. |