Teams had an early start at 3.45am, transported into the sound by Real Journeys, before the race was started at 6.30am by patron and nine-time Coast to Coast winner Steve Gurney.
Leading New Zealand teams made short work of the 8km paddle. Team Subway and Team Seagate were neck and neck into the first transition area with just a minute between them.
They were closely followed by Christchurch's Team One Square Meal and Australian team Blackheart.com.
After a lightning-fast transition the four teams headed up the Milford Rd towards the Homer Tunnel by bike.
Teams experienced the highlight of a pod of bottlenose dolphins "fully breaching out of the water", Australian team Hard Yuccas member Lisa Antill said.
Not much time separated the lead teams as they biked through the Homer Tunnel and down into the Upper Hollyford valley towards the Eglinton River.
From there, it was a smooth transition into inflatable kayaks for Team Seagate, Subway and One Square Meal.
At 2.30pm yesterday, race co-director Warren Bates said the teams were "blazing" through the first day and were ahead of projected race times by 20 to 30 minutes.
Last night, teams headed into their first night with a 54km trek over the Dunton Mountain Range just outside Te Anau.
"We expect the first teams to arrive at the Mavora Lake transition area in the early hours [today] but I have to say there is some tricky navigation on this trek, [particularly] for one checkpoint so they could spend some time bush bashing to try and find it.
"It's going to be exciting to see if the lead teams remain in their current positions but I'm not expecting them to sleep much, if at all, on the first night so they could move quite quickly."
Teams are travelling with satellite navigational tracking devices, to provide live progress reports online (www.godzoneadventure.com).
The first teams are expected across the finish line in Queenstown on Thursday but racers have until 2pm Saturday to complete the course.
