The shop has successfully stopped more than $500,000 worth of household and clothing items going to landfill.
It is just five years since they celebrated stopping $250,000 worth of items from going to landfill.
Shop manager Annette Patterson said the team was "super excited" about the milestone.
"We are absolutely thrilled to bits that we have managed to find homes for so many items for local people and people far away," Mrs Patterson said.
"Who would have known that this small shop could have reached a milestone so big?"
The shop has been open since July 2011, when students at The Catlins Area School’s middle school were working on an inquiry topic on saving the planet.
They opened the shop for one month and then community members took it over.
It is the only swap shop in South Otago, where items can be brought in and exchanged for vouchers, then redeemed for other goods in the shop.
Although the shop is only open for two and a-half hours a week, it has become popular in and out of the district.
"We get regulars all around the district who come along to swap items," Mrs Patterson said.
"It has blossomed into quite the little hub for locals, and recently we have been getting quite a lot of foot traffic, which is great.
"There is such amazing support from the community and our volunteers at the shop.
"We’re very thankful to everyone for their continued support throughout the years and we are proud to be celebrating this milestone."
The swap shop is just tracking along at the moment but has a Facebook page where people can see what they are up to and updates about the shop.
