The Aberdeen paddler, 34, won Britain's first gold medal in canoe slalom at London 2012 in the doubles with Bedford's Etienne Stott.
It was a day where everything went right for the pair who had been together for eight years and had their share of ups and downs. Baillie believes he cannot top that day and is not motivated enough to devote 24 hours a day, seven days a week in pursuit of another Olympic gold.
He has had months to mull over the decision after Stott dislocated a shoulder (for the second time in his career) at a World Cup race in Spain last summer, ending their season.
Stott has only recently returned to the water after surgery and will now seek a new partner for the new Olympic cycle. "Retiring from international canoe slalom racing has been a difficult decision which I've agonised over for a long time," said Baillie.
"I still love canoeing but I've realised that I no longer have the underlying desire required to commit all of my time to the singular pursuit of canoe slalom excellence.
"Looking back, the London Olympic cycle took a lot of energy, particularly fighting back from so many setbacks and I think that burned through my passion for the sport.
"Whilst my decision to retire is tinged with sadness, I feel Etienne and I have both had an incredible journey to look back on and a lot of exciting things to look forward to, so overall I'm feeling positive.
"I'd like to thank Etienne for all the adventures; it's truly a testament to our friendship that it's survived nine years of being strapped into the same canoe. Thank you to my wife, family and friends for all their support and understanding over the years.
"My parents in particular put my interests far beyond their own in providing me with incredible opportunities growing up and, most importantly, did it without putting any pressure on me to achieve results."
Baillie has revealed in the past that his partnership with Stott was almost accidental and came about the day after a canoe awards dinner when both were suffering from a hangover.
After an informal chat, they decided to team up in the doubles never suspecting it would end with an Olympic medal and, after that, MBEs.
Stott, 34, plans to continue in the sport and try for Rio with a new partner. "It's sad because it's the end of a chapter but I respect Tim's decision and it is the right thing for him," the Englishman said.
"I'm so proud and happy with the career that Tim and I had together, and very thankful for the good times, the hard times and the challenges that we've been through as a crew. It's taught me so much and developed me so far as an athlete, far beyond anything I would have dreamed of.
"I don't think that would have happened with another person and Tim has helped me so much. He has made a huge contribution to the sport and to me as an athlete."
Since winning gold in London, Baillie and Stott have been ambassadors for their sport, embarking on an endless run of appearances, ceremonies, dinners, media opportunities and school visits. Whilst supporting GB Canoeing's legacy projects, Baillie also discovered a talent for motivational speaking and that is something he is keen to develop this year.
"Having an incredibly up-and-down career with lots of interesting challenges and powerful lessons makes it a great story," he continued. "Since the Olympics I've really enjoyed public speaking as an opportunity to share what I've learnt about performing in a high pressure environment, so it is something I'm looking forward to continuing."
Paying tribute to Baillie, GB Canoeing Performance Director John Anderson MBE said: "Tim and Etienne are a fantastic pair of ambassadors for our sport. They always wanted to succeed, but the manner in which they wanted to do so was always in good spirit and good camaraderie with everybody around them.
"I'm sure that Tim has made the right decision for himself and the good thing is that he will continue to be a great ambassador for our sport."