"For me it's all about the adventure and having fun doing it at the same time," she said.
Brenna Roband, of Total Sport, said the company was excited to launch the new series and the feedback from around the country had been fantastic.
"For a long time, the Coastal Challenge has been one of Total Sport's most popular "must do" events," she said. "So there are a lot of excited people out there who are looking forward to conquering their piece of coast in some new locations. Many will be motivated to take the Coastal Challenge crown, but really these events are about providing people with an awesome and unique opportunity to get out there and challenge themselves, and share time with other like-minded people."
Mills is one of them. A few years ago she had friends doing the Full Monty distance and they persuaded her to enter the 16km event.
"I got the bug and have entered whenever I can since." She said the sense of adventure and going into the unknown were the biggest drawcards of the national series.
"I've run along some of the Wellington beaches before and I'm really looking forward to the early section from Oteranga Bay, fingers crossed for good wind and good views. I know the North Shore course pretty well but the Tawharanui course is a complete unknown for me - I'm expecting a bit of a swim, sandy beaches and some more great views."
She said the challenge of completing a 32km-35km run was a real physical and mental test.
"The distance is achievable but it does mean you have to put a bit of work in. The sea, tides and slippery rocks can be unpredictable and that adds to the challenge.
"At my pace in the run there's quite a bit of banter with the other runners and that always adds to the enjoyment."
Mills is running 60km a week in training at the moment. She is preparing for a 60km run at the Tarawera Ultra in February. She has low-key expectations in terms of performance for the Coastal Challenge.
"I'm more about the taking part rather than the winning, although I am competitive - even if it's just against myself," she said.
Coastal Challenge
1. Red Rocks, Wellington - November 15
2. North Shore, Auckland - March 7
3. Tawharanui, Auckland - April 25
Event options:
Beach Hopper - 6-7km run/walk
Bay Scrambler - 11-13km run/walk
Mini Monty - 17-21km run/walk
Mid Monty - 22-26km run
Full Monty - 32-35km run and team relay (for North Shore and Tawharanui events only)
For more information visit: www.coastalchallengeseries.co.nz