Marlins Roster & Staff
Transactions
| Date | Transaction |
| 06/30/18 | Miami Marlins recalled RHP Pablo Lopez from New Orleans Baby Cakes. |
| 06/30/18 | Miami Marlins optioned RHP Ben Meyer to New Orleans Baby Cakes. |
| 06/29/18 | Miami Marlins signed LHP Alex Vesia. |
| 06/28/18 | Miami Marlins recalled RHP Sandy Alcantara from New Orleans Baby Cakes. |
| 06/28/18 | Miami Marlins optioned RHP Nick Wittgren to New Orleans Baby Cakes. |
| 06/26/18 | RHP Dan Straily roster status changed by Miami Marlins. |
| 06/26/18 | Miami Marlins signed RHP Sam Bordner. |
| 06/26/18 | Miami Marlins signed OF Tristan Pompey. |
| 06/26/18 | Miami Marlins signed RHP Justin Evans. |
| 06/26/18 | Miami Marlins signed SS Osiris Johnson. |
| 06/26/18 | Miami Marlins signed C Cameron Barstad. |
| 06/25/18 | Miami Marlins recalled Ben Meyer from New Orleans Baby Cakes. |
| 06/25/18 | Miami Marlins placed LHP Caleb Smith on the 10-day disabled list. Left shoulder tightness. |
| 06/22/18 | Nick Wittgren roster status changed by Miami Marlins. |
| 06/22/18 | Miami Marlins placed RHP Jose Urena on the 10-day disabled list retroactive to June 21, 2018. Right shoulder impingement. |
| 06/21/18 | Miami Marlins signed C Will Banfield. |
| 06/20/18 | Miami Marlins signed RHP Zack Leban. |
| 06/20/18 | Miami Marlins signed RHP Jake Norton. |
| 06/20/18 | Miami Marlins signed RHP Tyler Jones. |
| 06/20/18 | Miami Marlins signed SS Luke Jarvis. |
| 06/20/18 | Miami Marlins signed RHP Jackson Rose. |
| 06/20/18 | Miami Marlins signed RHP Zach Wolf. |
| 06/20/18 | Miami Marlins signed RHP Eli Villalobos. |
| 06/20/18 | Miami Marlins signed RHP Joe Strzelecki. |
| 06/20/18 | Miami Marlins sent OF Garrett Cooper on a rehab assignment to New Orleans Baby Cakes. |
| 06/19/18 | Miami Marlins sent RHP Nick Wittgren on a rehab assignment to New Orleans Baby Cakes. |
| 06/18/18 | Miami Marlins signed RHP Cam Baird. |
| 06/18/18 | Miami Marlins signed RHP C.J. Carter. |
| 06/18/18 | Miami Marlins optioned RHP Merandy Gonzalez to Jacksonville Jumbo Shrimp. |
| 06/18/18 | Miami Marlins activated LHP Caleb Smith from the bereavement list. |
| 06/18/18 | Miami Marlins sent 1B Garrett Cooper on a rehab assignment to Jupiter Hammerheads. |
| 06/17/18 | Miami Marlins signed free agent RHP Jameson McGrane to a minor league contract. |
| 06/15/18 | Miami Marlins optioned RHP Ben Meyer to New Orleans Baby Cakes. |
| 06/15/18 | Miami Marlins signed free agent RHP Jared Crescentini to a minor league contract. |
| 06/15/18 | Miami Marlins recalled Merandy Gonzalez from Jacksonville Jumbo Shrimp. |
| 06/15/18 | Miami Marlins transferred LHP Chris O'Grady from the 10-day disabled list to the 60-day disabled list. Left shoulder sprain. |
| 06/15/18 | Miami Marlins placed LHP Caleb Smith on the bereavement list. |
| 06/15/18 | Miami Marlins activated RHP Brett Graves from the 60-day disabled list. |
| 06/14/18 | Miami Marlins sent RHP Nick Wittgren on a rehab assignment to Jacksonville Jumbo Shrimp. |
| 06/13/18 | Miami Marlins signed OF Milton Smith Jr. |
| 06/13/18 | Miami Marlins signed OF Harrison Dinicola. |
| 06/13/18 | Miami Marlins signed C Nick Fortes. |
| 06/13/18 | Miami Marlins signed SS Gunnar Schubert. |
| 06/13/18 | Miami Marlins signed RHP Cason Sherrod. |
| 06/13/18 | Miami Marlins signed RHP Tanner Andrews. |
| 06/13/18 | Miami Marlins signed 3B Andrew Turner. |
| 06/13/18 | Miami Marlins signed RHP Nathan Alexander. |
| 06/13/18 | Miami Marlins signed RHP Giovanni Lopez. |
| 06/13/18 | Miami Marlins signed OF Connor Grant. |
| 06/13/18 | Miami Marlins signed C Keegan Fish. |
| 06/13/18 | Miami Marlins signed OF Davis Bradshaw. |
| 06/13/18 | Miami Marlins signed RHP Jake Walters. |
| 06/13/18 | Miami Marlins signed RHP Peyton Culbertson. |
| 06/13/18 | Miami Marlins signed RHP Chris Vallimont. |
| 06/13/18 | Miami Marlins signed OF Connor Scott. |
| 06/12/18 | Miami Marlins signed free agent RHP Chad Martin to a minor league contract. |
| 06/07/18 | Miami Marlins optioned RHP Tyler Cloyd to New Orleans Baby Cakes. |
| 06/07/18 | Miami Marlins recalled RHP Trevor Richards from New Orleans Baby Cakes. |
| 06/06/18 | Miami Marlins selected the contract of Ben Meyer from New Orleans Baby Cakes. |
| 06/06/18 | Miami Marlins optioned RHP Odrisamer Despaigne to New Orleans Baby Cakes. |
| 06/03/18 | Miami Marlins selected the contract of RHP Drew Rucinski from New Orleans Baby Cakes. |
| 06/03/18 | Miami Marlins optioned LHP Jarlin Garcia to New Orleans Baby Cakes. |
| 06/02/18 | Miami Marlins placed RHP Nick Wittgren on the 10-day disabled list. Right middle finger contusion. |
| 06/02/18 | Miami Marlins recalled Tyler Cloyd from New Orleans Baby Cakes. |
| 06/01/18 | Los Angeles Dodgers traded 1B Peter O'Brien to Miami Marlins for cash. |
| 06/01/18 | Miami Marlins signed free agent RHP Tyler Mitzel to a minor league contract. |
| 06/01/18 | Miami Marlins signed free agent LHP Scott Sebald to a minor league contract. |