The shop has been opened for just six days and while trading was slow initially it's starting to snowball.
He's got some mates who skate and surf and they know what he's done. But for others Joshua's relying on Facebook and Instagram to promote the shop.
"It's about social media and word of mouth."
The Cullinane College student is too young to be the company director so until he turns 18 his father, Andrew, is standing in for him.
The D'Ath family is originally from New Plymouth and mum, dad and all seven kids have a taste for surfing and skateboarding. Even the youngest, one and-a-half year old Arthur, has had a ride on the front of his father's board.
Joshua has the shop open from about 1pm each day because he's at school before that.
But his father said there was another more pressing reason.
"The best surfing around here is usually in the morning so we can't let business interfere with that," he said.
