[1] He finished twelfth in the 200 m breaststroke at the 2008 Summer Olympics, and also set a new South African record (2:06.85) to earn a bronze medal at the FINA World Short Course Championships few months later in Manchester, England.

[2] Diering competed for the South African swimming squad, alongside his teammate Neil Versfeld, in the men's 200 m breaststroke at the 2008 Summer Olympics in Beijing.

Leading up to the Games, he captured the men's 200 m breaststroke title at the South African Championships in Johannesburg with a new national record of 2:11.88 to assure his selection to the Olympic team under the FINA A-cut (2:13.70) and shave 1.72 seconds off the standard previously set by Terence Parkin in 2000.

[5][6] Followed by the next morning's semifinals, Diering missed the top eight final with a twelfth-place time in 2:10.21, and lost a spirited challenge for another African record feat to Versfeld (2:10.06) by just a small fraction of a second.

[7] Shortly after the Olympics, Diering edged out Tunisia's Oussama Mellouli by nearly two seconds to claim the 200 m breaststroke title at the African Swimming Championships in Johannesburg with a time of 2:16.00.