Underwood was spotted running in Randolph's hometown of Huntington Beach, California, over the weekend, just weeks after the two called it quits.
And a source tells PEOPLE that while the two don't have any plans to get back together, Underwood and Randolph have seen each other "several times" since their breakup.
"Colton and Cassie are not back together, but they've been making a real effort to stay friends," says the source. "They’ve seen each other several times since Colton got back to L.A."
Over the weekend, the former Bachelor star was seen sporting a new, shorter haircut during the run while wearing a black t-shirt and matching shorts. The run marked his first public outing since the breakup.
Underwood, 28, and Randolph, 25, announced their split last month after over a year of dating.
"Its [sic] been a crazy few months to say the least, Cass and I have been doing a lot of self-reflecting. Sometimes people are just meant to be friends — and that's okay," Underwood wrote on Instagram at the time. "We both have grown immensely and been through so much together — so this isn't the end of our story, it's the start of a whole new chapter for us."
Randolph captioned her post, "Colton and I have broken up, but have decided to remain a part of each others lives. With all that we have gone through, we have a special bond that will always be there. I love Colton very much and have an enormous amount of respect for him. We have both learned and grown so much these past couple years, and will always have each others back. Always."
At the time, a source told PEOPLE the breakup was "amicable," stressing that the two were determined to remain friends.
"This is definitely amicable," said the source. "It was a mutual breakup. Colton and Cassie are still good friends, and they want to stay friends. It’s definitely a priority for them. Colton is sad, but he’s looking forward to what the future may bring."
A second source said: "The breakup happened recently. And they put a lot of thought into it. Ultimately, Colton and Cassie just weren’t on the same page. Colton really wanted to settle down and get married — he’s been ready for a long time. And Cassie just wasn’t ready. They both knew it wasn’t going to work."