"He says he want to drive fire trucks.
"Every time he saw one, he got very excited," his mother, Leanne, said.
Lucas was one of the dozens of children who attended the Invercargill Plunket Water Fun Day at the weekend.
As a special attraction, a Fire and Emergency New Zealand crew visited.
Firefighter Shane Campbell said he first got the bug to become a firefighter when he was just a boy.
He and Lucas had a blast splashing water.
"It is great — this kind of opportunity for kids to have fun and learn about our work. The best thing is seeing their smiles."