The North Face-sponsored event is a 44km race from The Remarkables ski field to the Coronet Peak base building.
Allan arrived at the finish line in 2hr 19min 13sec, 3min 30sec ahead of Gavin Mason, of Wanaka, with Mike Kelly, of Queenstown, finishing a further 90sec back.
Defending champion Glen Currie, returning to endurance racing after a serious illness, was fourth.
The event, which attracted 50 individual competitors and 67 teams, was held in cold but sunny and clear conditions.
The race consists of a 2km ski or snowboard to The Remarkables base building, a 17km mountain bike ride to the Frankton end of Lake Wakatipu, a 7km paddle to Queenstown Bay, a 9km run to the foot of Coronet Peak and a 9km cycle up the Coronet Peak access road to the finish.
Race director Geoff Hunt said a highly talented field competed with some excellent individual results.
"Dougal was going to be hard to beat after taking the lead on the run.
As the winner in 2007, he knew what was expected of him if he wanted to take the title again," Hunt said.
Allan, who was 8th in the Coast to Coast longest day event this year, was pleased with his win.
"Conditions were perfect but skiing for me was definitely the hardest leg. I managed to get away on the run but the Coronet Peak road biking section was interesting as I only had my granny gear working," he said.
Wanaka physiotherapist Joanne Williams proved to be too strong for the rest of the women's open field, finishing in 2hr 47min 49sec.
"It was a great experience but it was definitely a bit of a grind in places," she said after finishing ahead of Roxburgh athlete Kath Kelly (2hr 54min 25sec).
Outside Sports Queenstown team Geoff Small, Jim Hawkridge, Steve Norton and Adrian Bailey won the open teams title in 2hr 6min 16sec.
Dunedin team Smashing It In the Dog, won the women's teams event in 2hr 32min 39sec.
Long-time competitor Eric Billoud, of Queenstown, was the fastest veteran man in 2hr 43min 22sec.
Samantha Wright, of Queenstown, defended her veteran women's title, crossing the line in 3hr 11min 23sec.
Alexandra's Blake Luff was the fastest junior in 3hr 3min 28sec.
Team Sportbase (Queenstown) was first across the line in the mixed team section in 2hr 15sec 47min.
The race raised funds for the Bruce Grant Youth Trust which was set up in memory of Queenstown adventurer Bruce Grant, who died after climbing K2, to support young Queenstown sportspeople in their endeavours.
