Three years after deciding he wanted to do the event, the 17-year-old finished second in the 15-18 year-old school grade at the multisport event.
The Roxburgh Area School year 13 pupil finished in 13hr 18min 10sec, which was also good enough for 10th male home and 11th overall.
It had been a while coming for McKinnel, who lives in Ettrick. Several members of his family had previously competed.
One of those was his father, John McKinnel, who had completed the race from Kumara Beach to Christchurch five times.
That left Tiaan in capable hands when it came to training, although it was something he did not jump straight into.
''I think I was about 14 years old when I saw it somewhere and I saw what they'd done,'' he said.
''I talked to Dad about it and I thought 'that's something I want to do'.
''But I had to wait till I was a 17-year-old because Dad thought the training would be too much at such a young age.
''Dad sort of tried to go out tramping or something [like that] at that young age, build a good endurance base for me so when it came to the training I was able to handle it.''
He was thrilled with how the race had gone, saying he enjoyed the kayak the most.
The toughest part was the run, as he contended with cramps and going through cold water.
He found the Teviot Valley where he lived an ideal place to train, with rocky creeks and quiet back roads.
It was not his first experience of an endurance event. He enjoys the 12-hour and 24-hour versions of rogaining.
In rogaining, competitors make their way around a series of checkpoints, having to navigate their way and collect as many as they can in the set time.
He said he enjoyed the navigation side and hoped that, combined with endurance races such as the Coast to Coast, would help him to one day complete the Godzone adventure race.
Alongside that, he plays rugby, linking with Dunstan High School where he is a utility back.
After leaving school he hopes to move to Dunedin and take a course to become either an outdoor guide or a sports coach.
He was unsure whether he would keep playing rugby or focus purely on multisport and go back to rugby later.
