The highlight of the morning was a superb effort from multi-Paralympic gold medallist Sophie Pascoe, who was well under the qualifying mark for the Commonwealth Games in the 200m individual medley S10.
The world record holder clocked 2:31.50, which is 14 seconds under the qualifying time and only six seconds outside her world record.
"It was a good swim from Sophie," her coach Roly Crichton said. "We are just starting our build-up campaign for Glasgow and then the Pan Pacific Championships so today was an encouraging swim and nice to get the qualifying out of the way."
Boyle and fellow London Olympians Glenn Snyders and Matt Stanley all impressed with confident performances in their respective heats to set themselves up for a tilt at qualifying times for the Commonwealth Games in tonight's final session.
Boyle clocked 1:59.05 in a comfortable performance, less than a second outside the qualifying time for Glasgow, finishing clear of the Capital quartet of Samantha Lucie-Smith, Tash Hind, Samantha Lee and Emma Robinson.
The fastest four times tonight also need to go under a combined time of 7:55.92 to qualify a team in the 4x200m freestyle relay.
Stanley clocked 3:53.30 to best heats in the 400m freestyle, just over four seconds outside his best and the qualifying mark.
Snyders, now based in Los Angeles, was impressive with a smooth swim in the 200m breaststroke 2:13.12, less than a second outside the Glasgow mark.
In other swims, USA-based Sophia Batchelor was fastest in heats of the 50m butterfly in 27.19, Otago's Kurt Crosland topped the men's 50m backstroke in 25.75, Caroline Baddock (North Shore) was best in the 200m individual medley heats in 2:20.47 and North Shore's Shaun Burnett topped heats of the 200m butterfly in 1:59.53, less than two seconds outside the qualifying time for Glasgow.
Tonight's finals session starts at 7pm.
