Swimming Quarries are Open For the Summer at Quarry Park Stearns County Parks shared the news to their Facebook page on May 19th: Quarry Park Swimming Quarries – Yes! They’re open! Quarry Park is open from 8 am to one-half hour after sunset every day of the year. The two swimming quarries are open whenever the park is open. So as long as it is within park hours, and of course the weather is permitting, you can go for a swim at Quarry Park. Get our free mobile app Along with the update on the quarries being swimmable, the Stearns County Parks department shared that children should always be supervised, and everyone should swim at their own risk as there are no lifeguards on duty.