Schimanski claimed bronze in the 50m backstroke during Saturday evening's session before winning the 100m breaststroke in 1m 18.87s.
O'Keeffe continued her fine form with bronze in the 50m backstroke and Smith picked up his second gold medal in the 100m breaststroke.
To top the evening off, the youngest swimmer in the Wanganui team, 12-year-old Sarya Lower, showed that she is a top prospect by sprinting to a silver medal in the 50m freestyle.
On Sunday morning O'Keeffe took bronze in the 200m freestyle with another open qualifying time of 2m 10.26s. That evening Sophie Couper gained her silver medal in the 16-year-old 100m backstroke, and O'Keeffe kept adding to her impressive medal haul with bronze in the same event for 15-year-olds. In the last event of the evening, 14-year-old Elena Forlong got in on the action with her bronze in the 200m butterfly.
As the team entered the last day of a busy meet, there were still more medals to come.
O'Keeffe capped off her hugely successful competition with her sixth medal claiming her fourth bronze, this time in the 400m freestyle, and young Lower picked up a bronze in the 100m butterfly .
Couper won her first gold in the 16-year-old 200m backstroke and Jacob Smith claimed bronze in the 50m breaststroke.
Schimanski signed off the competition by completing the treble in the girls' breaststroke events with yet another gold in the 50m race in a very slick time of 35.16s. Her swim was so impressive that only two other female swimmers, aged 19 and 20, could beat the 13-year-old's time.
Interim coach David Rudolph said overall the Subway Wanganui team once again performed exceptionally well with all 10 swimmers coming home with finalists' ribbons and six swimmers medalling.
"Solid performance from Stefan Hannan, Jaime Schimanski, Samantha Miller and Jazim Phillips resulted in several personal bests and finals over the weekend. Overall it was a very successful weekend for all the swimmers," Rudolph said.
The team now gets back into training before some of the members travel to the Manawatu Long Course Champs in Palmerston North in the first weekend of February.