Sinnamon (46) will be contesting the two-person team section with brother-in-law Martin Powley (42) for a 12th time.
Powley was unable to compete in 2005, so Sinnamon teamed up with Dave Rudge (Wellington) to win the veteran section.
"You'd think we'd be old enough now to know better," Sinnamon joked about his return to New Zealand's premier multisport event.
"In fact, things have been that horribly dry up here that I really should be spending the two days on the farm.
"There's just so much to do.
"I know I'll be up there wondering if I should be back dealing with the irrigation and harvesting the hay.
"But this event is just something so special.
"It is something everyone should be part of at least once in their lifetime."
Sinnamon has never failed to be amazed at the range of people contesting the Coast to Coast.
"There are all sorts of people doing it from all walks of life and with all sorts of abilities.
"One year, I saw this blind guy competing.
"It just blew me away.
"It kind of puts your own performance into perspective."
As a returning competitor, Sinnamon is wise to the pitfalls of an event which inspires about 900 competitors to tackle 247km of wild and unforgiving terrain.
"It's never the same course from one year to the next," he said.
"The weather will change the nature of the course every year, especially on the kayak section.
"And the run can be just brutal.
"There is only one way in, either by foot or helicopter, and even then helicopter access is doubtful.
"There will be people that have never beaten me, and may never beat me again, that will take me out.
"It's just that sort of run."
Sinnamon's advice to first-timers is to pack plenty of insect repellent and air-freshener.
"On the West Coast the sand flies will eat you alive, and the port-a-loos are an experience in their own right."
Another piece of advice from Sinnamon is to have a good support crew.
Favoured to take overall honours in the longest-day section this year is Aucklander Gordon Walker.
The defending champion has, along with Richard Ussher, dominated the event for the past five years, but in the absence of Ussher, Walker will be the one to beat.
Walker (37) first won the event in 2007, upsetting race favourite Ussher, who returned in 2008 to claim a third title.
Victory on Saturday for Walker will see him equal Ussher's feat of three wins.
The two would then be behind only Steve Gurney (nine wins), whose name is synonymous with the event.
Walker, who clipped 31min from the race record, will face strong competition from Trevor Voyce (Nelson), Dwarne Farley (Mt Maunganui), Dougal Allan (Foxton), Jacob Roberts (Christchurch and internationals Martin Flinta (Sweden), Luke Haines (Australia), Jakob van Dorp (Canada) and Kenny de Sousa (Brazil).
The international factor promises to dominate the women's section with West Coast-based Canadian Emily Miazga seeking a fourth title.
She will again be challenged by arch rival and Nelson-based Finn, Elina Ussher.
Rachel Cashin (Taumaranui), third in 2007 and 2008, and Brazilian national champion Camila Nicolau, Canadian national champion Ursula Tracz and Emma Wichardt (Sweden) are others who will be vying for the title.
