Dressed in fluoro colours, they heard from guest speakers about the R U OK? campaign before diving into the icy depths of Lake Wakatipu.
Organiser Ryan Morris said the R U OK? campaign started in Australia, and was a way to let people know it's OK to ask for help.
"It's one day, whether it's only one out of 365 in the year, to let people know it's OK to not be OK.
"I came from Sydney and I saw quite a negative scene in hospitality. Personally I've been in hospitality for 10 years and just saw that people having long days, rough hours, bad experiences, potentially turned to drugs and alcohol, and just depression overall.
"Things spiralled out of control with people not having money."
But when he got here, he said, he found the hospitality industry had many of the same issues.
"With this trend there wasn't much of an outlet in Queenstown for it, so wanting to bring this fluoro Fridays and R U OK? mentality to let people know there are people who want to listen."
The freezing water had attendees sprinting back to the safety of the shore after their dip.
"It's so cold, but it's for a good cause," one woman said.
Where to get help in NZ
Suicide/depression related
Healthline: 0800 611 116
Lifeline Aotearoa: 0800 543 354
Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO)
Samaritans: 0800 726 666
Alcohol Drug Helpline: 0800 787 797
General mental health inquiries: 0800 44 33 66
The Depression Helpline: 0800 111 757
