Who is, or was, the oldest competitive swimmer in the world?

Participating under the auspices of Masters Swimming Canada, which offers competitive swimming for contestants aged 25 years and upwards, the oldest competitive swimmer in the world was the late Jaring Timmerman, who died in Winnipeg, Manitoba, at the age of 105, in November, 2014. Remarkably, Timmerman did not start swimming competitively until 1978, but subsequently set a raft of Canadian national records, in the 85-89, 90-94, 95-99 and, most recently, 100-104 age groups.

Equally remarkably, he set his first world record, or records, on a day of days in April, 2009; at the age of 100, Timmerman set new marks for the 50-metres freestyle (twice), the 50-metres backstroke, the 100-metres freestyle and the 100-metres backstroke. Indeed, he improved on his own world record in the 100-metres freestyle shortly afterwards and, at the time of his death, all four world records still stood. In fact, in January, 2014, less than three weeks shy of his 105^th birthday, Timmerman was still competing, leading to the creation of a 105-109 age group in Masters swimming, solely to accommodate him.