That's what TB12 joked while soakin' up the sun on a yacht off the coast of Italy, firing footballs from the boat ... and proving he's still got the arm to play in the NFL!

The soon-to-be Hall of Famer dropped the 9-minute debut episode of his new vlog, "Last Week with Tom Brady," which is produced by Shadow Lion, where he did everything from watching Simone Biles in person at the Paris Olympics with his daughter Vivian, to hangin' on a beautiful yacht in the Mediterranean with Michael Rubin and others.

At one point in the ep, Rubin, founder of Fanatics, was on a jet ski ... a perfect opportunity for Brady to throw a few passes to his buddy out on the water.

The NFL record holder for passing yards and touchdowns completes one of two passes to Rubin ... and that's when Tom jokes he's still got it.

"I just wanna make sure all those young bucks in the NFL know if I still wanted to come out of retirement, they still got something to deal with," Brady said.

We'll assume he's joking (though he's in fantastic shape) ... he's 47 and says he rarely throws the football anymore. So, while Tom likely won't be suiting up for a game again, it doesn't mean he won't be around football.