Luke Sinclair at the Bluff signpost.
They began at Cape Reinga on November 7 and, after a break between Christmas and New Year, finished at Bluff on February 28.
Mr Sinclair told the Herald their girlfriends were not too keen on the idea - "They weren't too supportive of the idea at first but stuck in there" - and the couples were "somehow" still together.
After the first day reality set in and it became clear how painful the experience would be.
"At Ninety Mile Beach we got destroyed by blisters. The same flat beach for the first three days, the same foot motion, you just get blisters on blisters on blisters."
It wasn't just walking tracks they had to follow either. Mr Bristow said many "weren't really tracks at all".
"We did a lot of bush bashing to get through some areas. The scariest part was through Harper Pass, near Arthurs Pass, in the South Island. The rain became torrential and the rivers came up really fast."
Despite that it wasn't hard to focus on what needed to be done. Mr Sinclair said: "It was surprisingly easy, the trick was not to look too far ahead and keep minor goals on the way.
"The first goal was to get to the east coast, Whangarei, Auckland. Heaps of milestones, you just had to keep morale up the whole way."
Along the way he got food poisoning near Te Kuiti and Mr Bristow celebrated his 23rd birthday in the Tararua Ranges.
In the North Island they stayed mainly in tents and occasionally on people's lawns but in the South Island there were "huts everywhere".
The South Island landscape impressed him. "I'd never spent much time in the South Island and it was a big eye-opener. There's so much empty space there."
But Northland was the standout.
"What really surprised me was Northland. We followed the coastline the whole way into Auckland and it was incredible to see the beaches on the way and the people - they were the most generous people and gave us food, manuka honey and places to stay."
The pair raised $800 for Oxfam which Mr Bristow said wasn't as much as they'd hoped. "[But] we felt it was a good effort considering we had only two weeks between deciding to go and setting off."
Long journey
• Luke Sinclair and Kendall Bristow walked 3000km in about six million steps from Cape Reinga to Bluff to raise money for Oxfam.
• It took them 100 days.
• They estimate it was 95 days of actually walking and five days paddling the Whanganui River.
• The highlight: The Northland coast and people.
• The scariest part: Torrential rain at Harper Pass.