Soler's deal includes opt-outs after the first two seasons, sources said. If he opts out, Soler would hit free agency again at age 31 next winter.
A bit player during the Chicago Cubs' drought-smashing victory over Cleveland five years ago, Soler was voted MVP of Atlanta's six-game World Series win over the Astros. Soler hit .300 with three home runs and six RBIs.
Soler's three Series home runs matched the most for the Braves, equaling Hank Aaron in 1957, Lonnie Smith in 1991 and Ryan Klesko in 1995.
Marlins general manager Kim Ng said as Miami opened camp that the team had two needs: an outfielder -- particularly a center fielder, which Soler hasn't been, as he has primarily played right -- and offense.
Soler does fit that bill. He has 121 home runs and 343 RBIs in 661 career games with Kansas City, the Cubs and the Braves. He led the AL with 48 homers in 2019, and hit 27 home runs in 149 games with the Royals and Braves last season.
Soler defected from Cuba in 2011, established residency in Haiti and made his big league debut in 2014.
MLB Network was first to report news of Soler's agreement with Miami.
The Associated Press contributed to this report.