Mauao's only points came in the second half when Rotorua prop Mita Takuira was given 10 minutes in the bin by referee Hamish Warner for an illegality.
But Rotorua piled on five tries in the second half and never looked under threat against Mauao, who were in their first season in the competition.
Another standout for the red and blues was halfback Te Ra Whata.
In the 2nd XV premiership final, Western Heights High School blew a 12-5 halftime lead against Tauranga Boys' College to go down 20-17.
The under-15 premiership final was a tough battle between Mount Maunganui College and Trident High School. With both sides locked up at 10-10 at halftime and going try-for-try after the break, the match wasn't decided until the last couple of minutes, when Trident converted a penalty and scored a try on fulltime to win 23-15.
A Rotorua derby between Rotorua Boys' High and Rotorua Lakes High in the division three final was a one-sided affair, with Boys' High maintaining their unbeaten season record in a 35-5 victory.
In the division two final Aquinas College were no match for Reporoa College, who won 38-0.