Towards the end of their ride, a security guard spotted the four boarders and told them to leave.
"And we told him that we were leaving anyway, but then he just started sprinting at us and we just started running," Joel, 17, told the Herald.
"Then he caught up to my friend [Jerome] and took his board."
Jerome then started filming the confrontation.
At the start of the footage, which has been viewed on YouTube 10,000 times already, the guard comes over to the group with Jerome's board in his hand and says: "You know that you're trespassing on private property and I'm on the phone to the police?"
Jerome tells him that the gate was open, and they argue over the board as the group is escorted out of the stadium.
The situation escalates when they reach the exit, and there's pushing and shoving between the guard and Jerome as he tries to get his board back.
The security guard then loses his temper and goes to smash the board on the door, but hits 16-year-old Ethan with it as he swings.
The guard then smacks the board against a metal pole, while saying in between blows: "I'm breaking it and I'll keep breaking it."
Just outside the gate, he asks: "You want your board back? Here it is, here it is," as he snaps it in half.
"There's your board."
Joel said the group knew they were in the wrong and wouldn't go back to Eden Park, but called the guard's actions "pretty uncalled for".
The skateboarders uploaded the footage so people could see their side and how aggressive the security guard got, not for an apology, Joel said.
Eden Park spokeswoman Tracy Morgan said only that there was a break-in at the park on Saturday and that the people were caught and evicted.
"And we're not going to make any further comment."
