Jake Burger, Jacob Stallings and Jazz Chisholm Jr. also went deep for Miami, which snapped a modest two-game skid by taking the opener of the three-game series.
The power display provided more than enough run support for Marlins starter Sandy Alcantara (6-10), who allowed three runs on seven hits in six innings. He walked one and struck out six.
Mookie Betts, Max Muncy and James Outman homered for Los Angeles, which hadn't lost since Aug. 5. Will Smith chipped in with a pair of hits.
Dodgers starter Tony Gonsolin (8-5) was shelled for 10 runs on eight hits in 3 1/3 innings. He walked four and fanned two.
Both leadoff hitters opened their team's half of the first with solo shots, as Soler blasted his 31st homer before Betts cranked his 32nd in the bottom of the inning.
Soler put the Marlins back on top with another solo homer in the third. Miami blew the game open later in the frame, getting a three-run homer from Burger and two-run shot from Stallings to take a 7-1 lead.
The Marlins kept pouring it on in the fourth. Soler drew a leadoff walk and Luis Arraez followed with a double to set the stage for Chisolm, whose one-out home run made it 10-1.
Muncy pulled the Dodgers within 10-2 with a solo homer to open the fourth, but Los Angeles seemingly surrendered an inning later, pulling Betts and star first baseman Freddie Freeman from the game.
Miami struck again shortly after the duo's departure, going up 11-2 thanks to Joey Wendle's RBI triple in the fifth.
Los Angeles got that run back in the bottom of the fifth when Outman hit a solo shot.
The Dodgers had a rally in the works in the eighth after loading the bases with no outs, but they came up empty, as Amed Rosario lined out, Outman struck out and Miguel Rojas grounded out to end the inning.
Rojas, a shortstop, pitched a 1-2-3 ninth.
—Field Level Media