Coakes, the open women's champion, open men's champion Tane Wallis (Piha) and under-20 champion Harrison Whiteside (Christchurch) all claimed debut New Zealand Pro Series titles.
The final day of the event was held in ideal conditions, with a solid 1.5m swell hitting Aramoana Spit.
Offshore winds prevailed throughout the day, making for exceptional peaks and offering big power pockets and barrels.
Coakes, who surfed outstandingly all weekend and posted high scores on day two to qualify, maintained her form yesterday to beat Alethea Lock (Christchurch) in the final.
For Lock, it was a second runner-up placing of the year.
Third-placed Nicola Jones did enough to leapfrog fellow Christchurch surfer Kristi Zarifeh and take the No 1 ranking after four rounds of the series.
Wallis won the most dramatic of finals, coming from behind to pip Gisborne stalwart Maz Quinn on the last wave of the event.
Wallis led at the start of the final, but Quinn bounced back with 7-point and 8-point rides to jump into the lead.
With time running down, the two surfers paddled out for an approaching set.
The first wave was so nice that Wallis decided to ''hoot'' Quinn into the first wave.
Quinn smashed the wave to bits, posting another 8-point ride.
But it was the wave behind that finished the event in the best possible way.
Wallis stroked into a perfect wave, pulled into the barrel and was spat out five seconds later at the end of the wave, to score a perfect 10-point ride and the victory, his first in the open men's division.
Despite not winning the event, Quinn jumped into the lead in the New Zealand Pro Series with one event remaining, and is a good bet to defend his 2013 title.
Dunedin surfer Jamie Civil was third in the open final and Hugh Ritchie (Christchurch) fourth.
Ritchie moves up to third on the South Island circuit rankings behind leader Levi O'Connor (Kaikoura), who holds off Whiteside for the No 1 spot.
Whiteside won the under-20 final at the Spit, pipping Wallis, who was unable to secure the weekend double.
Whiteside moves into second place on the national rankings and extends his lead on the South Island circuit, having won three of the four events contested.
