The Phins used the running game with safe passing plays to work their way to the end zone.
Ricky Williams busted up the middle for a four-yard touchdown as rookie kicker Dan Carpenter went 4-4 on his field goal attempts. Ted Ginn, Jr. led all receivers with four catches for 58 yards.
The Dolphins' defense was superb, shutting down the Jaguars' high-powered offense until the late stages of the fourth quarter.
Jags running back Chris Brown ran three yards for Jacksonville's first touchdown. Their quarterback Todd Bouman added a 12-yard touchdown strike to Charles Davis.
That would be all the scoring the Jags would get on Miami's defense.
Miami will look for their second preseason win when they take on the Kansas City Chiefs.
Chad Pennington will most likely start, as he proved how accurate he can be going 5-of-6 for 55 yards. Chad Henne should be the immediate back-up, as he was solid going 17-of-26 for 133 yards.
It is still a mystery who will be named the starting quarterback, but it is shaping up to be a great battle between Pennington and Henne.
Apologies to quarterbacks Josh McCown and John Beck, but they are lagging behind the Chads in this competition.