The actor just shared a series of shirtless thirst traps from a recent getaway to Idaho with his brother Dylan, who is giving his more famous sibling a run for his money when it comes to hotness.

Zac and Dylan both ditched their shirts during a boat day out on Lake Coeur d’Alene, where they showed off their abs and chiseled bodies as they did some wakeboarding.

The Efrons also hit the links for a round of golf ... and Dylan says Zac came out on top ... though Dylan says he got revenge by pushing Zac into the lake.

There are a lot of thirst traps, but also some wholesome family content ... and even some snaps of Zac falling off his wakeboard.

Zac's always been known as a super hottie but his Hollywood producer brother is coming in hot here soo ... so we gotta ask.