January 02, 2019

Mariners  sign Yusei Kikuchi as a free agent

Mariners  sign Aaron Northcraft

January 10, 2019

Mariners  designate John Andreoli for assignment

Mariners  sign Tim Beckham as a free agent

January 21, 2019

Shed Long traded from Yankees  to Mariners 

January 24, 2019

Mariners  sign Austin Nola

Mariners  sign Tommy Milone

Mariners  sign Nabil Crismatt

Mariners  sign Tyler Danish

Mariners  sign Jose Lobaton

Mariners  sign Tayler Scott

Mariners  sign Tim Lopes

January 27, 2019

Mariners  sign Hunter Strickland

March 18, 2019

Mariners  place Shawn Armstrong on the injured list

Mariners  place Kyle Seager on the injured list

March 19, 2019

Mariners  place Anthony Swarzak on the injured list

March 29, 2019

Tom Murphy traded from Giants  to Mariners 

March 30, 2019

Mariners  place Kyle Seager on the injured list

Mariners  place Hunter Strickland on the injured list

April 02, 2019

Connor Sadzeck traded from Rangers  to Mariners 

April 14, 2019

Mariners  place Wade LeBlanc on the injured list

April 24, 2019

Mike Wright traded from Orioles  to Mariners 

April 26, 2019

Mariners  designate Shawn Armstrong for assignment

May 04, 2019

Austin Adams traded from Nationals  to Mariners 

May 10, 2019

Mariners  place Dylan Moore on the injured list

May 17, 2019

Mariners  designate Zac Rosscup for assignment

May 19, 2019

Mariners  designate Mike Wright for assignment

May 20, 2019

May 21, 2019

Mariners  place Dee Strange-Gordon on the injured list

Mariners  sign Anthony Bass as a free agent

May 29, 2019

Mariners  place J.P. Crawford on the injured list

June 02, 2019

John Andreoli traded from Twins  to Mariners 

Jay Bruce traded from Mariners  to Phillies 

June 04, 2019

Mariners  place Connor Sadzeck on the injured list

June 05, 2019

Mariners  place Braden Bishop on the injured list

June 07, 2019

Mariners  place Mitch Haniger on the injured list

June 11, 2019

Mariners  sign Nick Duron

June 14, 2019

Mariners  place Brandon Brennan on the injured list

June 23, 2019

Mariners  designate Jesse Biddle for assignment

July 04, 2019

Matt Wisler traded from Padres  to Mariners 

July 05, 2019

Mariners  designate Mike Wright for assignment

July 06, 2019

Mariners  place Dan Altavilla on the injured list

Mariners  place Austin Adams on the injured list

July 23, 2019

Mariners  place Dee Strange-Gordon on the injured list

Mariners  designate Parker Markel for assignment

July 26, 2019

Mariners  place Tim Lopes on the injured list

July 31, 2019

August 05, 2019

Mariners  place Tim Lopes on the injured list

August 09, 2019

Jose Lobaton traded from Mariners  to Dodgers 

August 15, 2019

Mariners  place Brandon Brennan on the injured list

October 31, 2019

Arodys Vizcaino became a free agent

Wade LeBlanc became a free agent

Tommy Milone became a free agent

November 25, 2019

Nestor Cortes traded from Yankees  to Mariners 

November 26, 2019

Mariners  sign Kendall Graveman as a free agent

November 27, 2019

Mariners  sign Patrick Wisdom as a free agent

Mariners  sign Jose Marmolejos

December 02, 2019

Tim Beckham became a free agent

December 04, 2019

Mariners  sign Carl Edwards as a free agent

December 05, 2019

Omar Narvaez traded from Mariners  to Brewers