An exhausted, but surprisingly alert, Fiona (Fi) Fairbairn exited Lake Wanaka last night after an epic 45km length of the lake swim.

Welcomed by an estimated crowd of 400 well wishers, Fi completed her swim by promptly standing up and walking unaided from the lake just after 10pm (Friday January 18).

The unofficial time for Fi’s swim is 16hrs 10mins.

“I wouldn’t wish it on anybody” Fi said as friends and family embraced her with congratulatory hugs.

Fi’s swim began at the lake headwaters at Makarora and finished in Roys Bay.

Yesterday's swim reprises a 37.5km attempt Fi made on March 30 last year when she came agonisingly close to completing the distance but the cold got the better of her and her support crew pulled her out near Stevenson’s Peninsula, just as the end was in sight.

Fun fact: The English Channel is a 33km swim

The swim was a fundraiser for the Darryl Fairbairn Memorial Fund, named after Fiona’s late husband, who committed suicide 15 years ago. Late last night the total raised was just over $6,000.

The charity supports Upper Clutha children and families suffering from grief or trauma. It is administered by Community Networks and donations are tax deductible.

A large crowd gathered to welcome Fi at the end of her swim.

The Wanaka Lake Swimmers Club is aware of just one other person who has attempted the length of Lake Wanaka, Kai Whakapai co-owner Roger North, but does not know of anyone who has successfully completed the challenge.

People wanting to donate can do that at Wanaka Community Networks in Brownston Street or through the Darryl Fairbairn Memorial Fund’s Give A Little Page.

PHOTOS: Wanaka App