The ocean is their playground, with so many toys from which to choose. But all are variations on the same theme, that of being out on the water.

Windsurfing, tow-in surfing and outrigger paddling were just pupu for Kai Lenny and Connor Baxter growing up on Maui. Pupu that whetted — and wetted — their appetites for what has become their passion and their profession: stand-up paddling.

The two are among the best in the world at SUP, a sport that has been riding an amazing wave of popularity around the world for the past few years.

Both are among the favorites at this weekend’s North Shore Paddle Challenge at the Turtle Bay Resort, the finale of the California-Hawaii racing season. There is $15,000 in prize money to be had in the two-day event, which includes Saturday’s sprint-surf slalom run and Sunday’s downwinder from Turtle Bay to Haleiwa.

"I’m really excited to be racing back at home," said Baxter, who turned 17 last month. "Summer was a lot of fun, with a contest almost every weekend. I was traveling a lot. Oregon to Utah to Miami and California. It’s been pretty amazing."

Baxter won the elite SUP race at last month’s Battle of the Paddle-California, was third overall at May’s BOP-Hawaii and became the youngest SUP champion in the Molokai-2-Oahu Paddleboard World Championship in August, breaking the record by 30 minutes and finishing ahead of the prone paddleboard field.

That he’s come so far so quickly has surprised Baxter, whose goal at age 8 was to become a world champion in windsurfing.

"But about four years ago my dad said to try this (stand-up paddling) and, I don’t know what it was, I got hooked," Baxter said. "Growing up over here, it’s hard not to get incorporated with the water. I chose to do all the water sports.

"I’ve surfed Jaws (big-wave surf break off Pe’ahi, Maui), I’ve tow-ed surfed it, did stand-up. I remember my first wipeout there. It just made me want to go back out and conquer it."

It’s been the same feeling for Lenny, who turned 19 last Saturday. He, too, loves Jaws "with the most perfect big waves on planet Earth," he said. "I towed-out my first time at 16, got to windsurf it last year.

"But I’m looking forward to this week. There should be a swell running and I’m super stoked. I don’t know who all is coming, but I hope everyone comes because you want the best guys here. If they aren’t, you question what would have happened if they had been here and you don’t want that question."

No one has questioned Lenny’s abilities all tour season as he defends his Stand Up World Tour title. He is the runaway leader in the SUWT standings, with two wins, a third and a fourth with two events remaining.

Organizers expect up to 250 competitors this weekend and are not capping entries. Online registration is still open for all divisions. Some of the other top athletes expected are Danny Ching, Slater Trout, Dave Kalama and Aaron Napoleon.

This weekend’s event also showcases the racing format that will be used for the Stand Up World Series, which begins next year.