Informing people about the 5-knot rule was a major part of the safety induction his business did with customers before they headed out on jet skis.
While most people were good, some seemed to forget everything they had just been told, Mr Carr said.
"We yell at our own customers. We have to tell a lot of them to slow down."
Tauranga Harbourmaster Peter Buell said the number of infringements and warnings issued were few when compared with the number of people out on the water this summer.
"A big part of our message at this point is that boaties in general are obeying the rules very well. Of course, there are always exceptions and when these people are around they are very obvious.
"We will remain vigilant in our patrols."
Mr Buell said he had been surprised at the lack of understanding around lifejackets and paddle boards.
"In the surf you may be without a lifejacket, provided you have your leg strap on. At all other times a lifejacket is required," he said.