Valerie Grand'Maison of Fleurimont, Que., and Calgary's Brianna Nelson each won their second silver medals of the Games at the pool, while wheelchair sprinter Brent Lakatos of Dorval, Que., also won silver in the 400 metres Sunday.
Eight of Canada's first 11 medals have come from swimmers and the remaining three from track and field.
Grand'Maison was an arm swing away from gold in her signature event, the 100-metre freestyle.
For the second time in as many days, she was narrowly beaten for the top step on the podium by Kelley Becherer of the U.S.
Grand'Maison had finished second to the American in the 50-freestyle the previous day.
"I'm going to be emotional for the next few hours," Grand'Maison said. "It was a close one. I race Kelly, the American, all the time. It's always a close finish. It's always be a few tenths or a few hundredths. She's a way better sprinter than I am, so her first half is really strong compared to mine.
"Tonight, I tried to stay with her because I wanted it so bad. I tried my best and I was with her at the 50. I knew it my time to shine. I just didn't have it in me."
Canada's objective in London is a top-eight finish in gold medals won. Canada had three gold after five days, tied for 13th with Iran and South Korea.
Grand'Maison, who is visually impaired, was Canada's most successful swimmer at the 2008 Paralympics in Beijing with three gold medals and a bronze. She set a world record in the 100 freestyle there, but a shoulder injury in 2011 almost ended her career.
"A year ago I would never thought I would have been to that level of fitness right now," the 23-year-old said. "The way we turned the program around. My strength and conditioning program, working with a sports psychologist, physio, I did everything I had to do and I have no pain right now. I love racing again."
Nelson, who has cerebral palsy, was second to Jaqueline Freney of Australia the women's 200 individual medley, two days after taking silver behind the Aussie in the 50-metre butterfly.
"This is my second Games. I wanted to be somebody here," said Nelson, 20. "In Beijing, I was there to have fun. I wanted to be ferocious this time. I'm feeling ferocious."
Grand'Maison races the 200 I.M. and 100-metre breaststroke later this week.
"It's not over," she declared. "I'm going to fight harder. In the last four years, I've gone through a lot of challenges and right now, it's just one more challenge that I have to overcome and it will make me stronger in four days when I race again, when I show up on that pool deck again, fierce, mean and ready to show what I've got, finally."
Lakatos wheeled to silver in the men's T54, or paraplegic, classification. The 32-year-old's time of 50.17 was second to the 49.70 posted by China's Li Huzhao.
Lakatos was paralysed in a hockey accident at the age of six. The Canadian lives and trains in Dallas, Texas and is married to Stephanie Reid, an amputee who won bronze in the 200 metres for Canada in 2008. She's representing host Britain at these Games and won silver in the long jump Sunday.
"It's great to have her to share it with," Lakatos said. "It's really special.
"The bet was whoever wins gold doesn't have to do the dishes."
Lakatos said he encouraged his wife, who has a Scottish father and an English mother, to join the British team for 2012.
"I was actually kind of pushing her in that direction," he said. "I thought it would be a good decision for her.
"The training environment, the coaching, the high performance centres, everything. It's a great place for her to be where she can receive the best training and get her in the best shape she can to have the best result."
In other swim finals Sunday, Sarah Mehain of Vernon, B.C., was fifth behind teammate Nelson in the individual medley. Vancouver's Donovan Tildesley placed seventh in the men's 100-breastroke in a visually impaired classification.
Winnipeg's Rhea Schmidt was eighth in Grand'Maison's event, the 100 freestyle. Calgary's Morgan Bird was also eighth in the women's 50-metre freestyle.
Also at the track, wheelchair racer Diane Roy of Sherbrooke, Que., was disappointed in her ninth-place finish in the women's 5,000 metres. She'd initially won gold in the distance in Beijing only to have to re-race it because of a protest. Roy was then second in the re-race. Teammate Keira-Lyn Frie of Saskatoon was fourth Sunday.
Bo Hedges of Wonowon, B.C., scored 24 points in a 73-66 win over Germany in men's wheelchair basketball. Unbeaten in four games, the Canadian men clinched first place in their pool.
The women's team improved to 2-1 with a 65-61 victory against Brazil. Vancouver's Janet McLachlan led the Canadians with 36 points and 23 rebounds. The Canadian women will play in the quarter-finals.
Canada won its first game in women's goalball, with Amy Kneebone of Charlottetown scoring twice in a 3-1 victory over Sweden. The men's team fell 8-6 to Algeria.
Robbi Weldon of Thunder Bay, Ont., and pilot Lyne Bessette of Knowlton, Ont., were seventh in track cycling in the individual pursuit for visually impaired
Joan Reid of Enderby, B.C., was sixth in single sculls for rowers who have only the use of their arms and shoulders. The mixed four crew with cox including Anthony Theriault of Nanaimo, B.C., Ottawa's David Blair, Toronto's Victoria Nolan, Winnipeg's Meghan Montgomery and cox coxswain Kristen Kit of St. Catharines, Ont., was seventh.
Eleonore Elstone of Langley, B.C., and Ottawa's Jody Schloss were seventh and 11th respectively in Para-dressage.