Kathmandu is set to phase out conventional cotton completely by 2020.
The target has been set out in Kathmandu's 2016 Sustainability Report.
Kathmandu increased its use of sustainable cotton from 38% to 59% this year.
Kathmandu textile r&d and responsible materials manager Manu Rastogi confirmed progress is underway.
"We care about promoting and protecting workers’ rights throughout our supply chain, and improving working conditions," Rastogi said.
"We also care about sustainability and protecting the outdoor environment we love to play in.
"As we use cotton in a range of our products, it’s important the cotton we use is environmentally–friendly and ethically produced."