"We don't get many chances to compete in open-water races, so this series is really important.
"Even though the Olympic distance is 10km, and these are shorter, they give you more experience in open-water swimming to get some valuable racing and to practise the skills you need in open-water competition."
Radford, who is coached by Mark Regan at Swimming New Zealand's High Performance Centre, said choosing the best course was the key to success across the harbour.
"I took a bad line last year and was miles off course. Navigation is a big part of these races. For me, this race is the first step and I am looking to get my confidence up with a good performance."
Radford has been in strong form of late, winning the Tiburon Mile in San Francisco and the Queensland 10km title.
He comes up against a super-strong field led by Australia's top open-water swimmers, brothers Trent and Codie Grimsey. The latter won last year's State Harbour Crossing and was pipped by just one second by Radford in San Francisco.
"They are both classy swimmers who travel a lot for open-water racing. With them in the field, it will be a great race and it's exactly the type of competition I need."
Also lining up is another super-talented young Australian, Jarrod Poort; up-and-coming Howick Pakuranga teenager Stephan Talbot; brothers Andrew and Jonathan Pullon, who competed at the World University Games; and leading pool swimmer Kurt Basset.
Queensland-based Kiwi Cara Baker will be back to defend her harbour crossing title in the women's competition and will no doubt be looking to chase along some of the male swimmers. Like Radford, the 21-year-old has her sights set on Olympic qualification, with the harbour crossing her first open-water competition since finishing 22nd at the world championships in Shanghai, where she suffered in the extreme heat.
She is pleased with her training under legendary Australian coach Dennis Cotterell, who guided the career of the great Grant Hackett.
"I can't wait to compete again," Baker said. "I love the harbour crossing race. It's so special to swim across the harbour and alongside the harbour bridge.
"The New Zealand Ocean Swim Series is great. It's an important part of my open-water preparations and the competition this summer is going to be fantastic."
Baker will have some interesting competition in the form of the well-performed Australian international Stacey Hansford and New Zealand's top-ranked female pool swimmer, Lauren Boyle.
The series
Harbour Crossing, Auckland, Nov 13
Paihia Classic, Bay of Islands, Dec 10
Capital Classic, Wellington, Jan 29
La Grande Swim, Akaroa, Christchurch, Feb 19
Sand to Surf, Mt Maunganui, Mar 10
King of the Bays, North Shore, Auckland, Mar 31
For more information and to register visit www.oceanswim.co.nz