The 2022 Coast to Coast sold out in just under five minutes after entries opened at midday on Monday.
1000 entries were snapped up, with nearly another 1000 hopefuls now on a wait-list.
Entries for the events' major category, the Longest Day, saw the most entrants in its history since being introduced in 1987, with over 300 people entering to take on the gruelling 243km course in one day.
Race director Glen Currie said it was a great turnaround from seven years ago, when Trojan Holdings purchased the event with just 460 entries in total.
"It's hard not to be disappointed for the people who missed out, but it's also a reflection of how much hard work and dedication that's gone into the event to make it a favourite with Kiwis, Aussies and multi-sporters from around the world."
While Covid-19 had been tricky to manage, he felt the increased demand for space was in part down to Kiwis wanting to get out and about in the outdoors.
"The feedback we're getting is Kiwis are again falling in love with their own backyard and as a result the Kathmandu Coast to Coast is again a must-do for Kiwis all around New Zealand, New Zealanders are travelling near not far."
Currie, who runs the event with just three others and a mountain of volunteers, said the team was feeling humbled, honoured and excited about the level of interest in the event.
"Running events is hard, really hard, especially with Covid-19, health and safety and the commercial pressures that come with operating an event like this. But when people react like they have and sign up, well that just makes it all worthwhile."
People on the waitlist will be contacted in the next week.