In semifinal play, Koch whitewashed clubmate Maree Gopperth 6-0 6-0, with Caskey having a much closer battle against her clubmate Sophie Robertson before prevailing 7-5 6-4. Caskey later won the girls' 18s singles, with Robertson winning the girls' 16s singles.
"I'm pretty happy to get my fifth singles title," said Koch afterwards admitting to being a little tired after a busy weekend on the courts.
"I played well in the singles and the combines, but not so good in the doubles. It was my first time playing with Shenae (Manawatu's Sheane Salisbury). We lost in the tiebreak," she said.
"It's always good to play in this tournament. I look forward to it every year. And playing in the combines and winning with my brother Cameron was special."
Sydney's Jono Hurley made it back-to- back titles when he won the open men's final. In a rematch of last year's semi-final, the No 1 seed beat Koch's brother Cameron 6-3 7-6 to claim his second Taranaki open men's title.
In the semifinals, Hurley cruised past Okaiawa's Andrew Powell 6-1 6-2, while Koch had to work hard to head off Bayden Stevenson, of Wairarapa, 6-4 7-5.
Cameron and Nicole then combined to win the mixed open doubles title, with a 6-0 6-0 clean sweep over Powell and clubmate Amelia Weir.
The open men's plate final was won by Okaiawa's Mark Laurence who beat Pukekura's Brady Simpson 9-6. Laurence couldn't make it two titles when he was beaten 7-6 6-3 by Manaia's Jacob Gopperth in the men's B grade final. The B grade doubles was won by Jaime and Brady Simpson 9-5 over Laurence and Andrew Baylis, while Malcolm Baylis (Okaiawa) and Steve Hurley (Wairarapa) won the social men's doubles.
Pukekura's Mike Fleming won his seventh Taranaki Open men's doubles title when he combined with Cameron Koch to take the 2012 title 6-4 6-4 over Brisbane's Frayne Bloor and Tim Low. In semifinal play, Bloor and Low beat Hurley and Stevenson 6-2 6-4, while Fleming and Koch beat the Pukekura pairing of Callum Old and Jamie Simpson 6-2 6-1.
The women's doubles went the way of Caskey and Frances Gray (Rotokare) who beat Nicole Koch and Salisbury 9-8, taking the tiebreak 7-3.
Okaiawa's Hamish Mead added the boys' 16s singles title to the 14s boys title he won earlier, winning the final with a 6-7 7-5 victory over Brady Simpson who retired before the third set. The boys' 12s singles went to Manawatu's Kurt Amey who beat Callum Sutherland of Huatoki 6-4 6-3, with Huatoki's Hikaru Han beating Kyra Allan from Perth 6-0 6-0 in the girls' 12s singles final. The 10s boys' singles was won by Jayden Harrison defeating Charlie Waite 9-1. The girls' 14s singles title went to Shenae Salisbury (PN) who defeated Ellen O'Byrne (NP) 6-3 6-1, whilst the 16s girls' singles was won bt Sophie Robertson. In the 18s, Thomas Burrell was the boys' champion and Alice Caskey was the girls' champion.
Cole Hareb (Rotokare) and Ajeet Rai (Huatoki) won the boys' 16s/18s doubles final with a 9-5 win over Brady Simpson and Sutherland.
Other doubles winners were: Boys' 14s, Hareb and Rai 6-0 6-1 over Mead and Logan Amey (Manawatu); girls' 12s, Han and Alexandra Spurdle (Pukekura); boys' 12s, Jayden Harrison and Callum Sutherland (Huatoki) 6-0 7-5 over Caleb Fleming (Pukekura) and James Weir (Hawera); 10s boys, Jayden Harrison/Charlie Waite; 14s girls, Hikaru Han/Shenae Salisbury
Plate winners were: Boys' 14s singles, Blake Kalin (Manaia); boys' 16s singles, Cole Hareb (Rotokare); boys' 12s singles, Conor Backhouse (Manawatu); girls' 12s singles, Jemma Loveday (Auckland), boys' 10s singles, Oscar Wano (NP)