Another year older and hotter than ever!

One day after Nick Lachey turned 38 and Vanessa Minnillo turned 31, the newlyweds showed off their super hot bodies on a bike ride in Maui.

On Thursday, shirtless Lachey showed off his six-pack and a bikini-clad Minnillo flaunted her toned tummy as they soaked up the sun and got in a workout.

An eyewitness told Us Weekly the couple "arrived on the night of their actual joint birthday and [Nick] had a romantic dinner set up for the two of them by the beach. She seemed very happy and totally in love with him. They were hugging, kissing, laughing and toasting throughout the meal."

The couple, who wed in July on Necker Island after four years of dating, recently bought a $2.85 million mansion in Encino, Calif., but they sure do love their beach vacations!

Whether it's a honeymoon in St. Barts or a romantic vacation in the Bahamas, Minnillo and Lachey's healthy lifestyles are evident every time they strip down to a bikini or swim trunks!

Before her wedding, Minnillo worked out with celebrity trainer Gunnar Peterson three times a week.

"I want [Nick] to see the girl he fell in love with," the 5-foot-7 stunner told Us of skipping crash dieting in favor of a five-meal-a-day delivery service. "I want to stay true to who I am, but, you know, a better version."

"He trains me like an athlete," she said of doing agility drills and complex strength-training moves with Peterson. "When I started, I remember thinking, 'Ugh, I'm trying to win the Super Bowl!' But now I like it."