Penticton became an option after it was recommended by Flyers development coach Brett Hextall, who played there for two seasons (2006-08). O'Brien said his first visit sealed his decision.
"It was beautiful," he said. "The facilities, support from the fans and the town is unbelievable."
His plan is to play one season with Penticton, then try college hockey again in 2020-21, this time at Boston University.
"My old coach (at Thayer Academy) Tony Amonte went there, I know a bunch of people there, Joel (Farabee, Flyers forward prospect), everybody loves how they play, how much fun they have playing hockey and going to school," he said. "I toured a few times, felt right at home. It's going to be a good fit."
O'Brien's offseason has been about continuing to put his past behind him and focus on the future. He said he was healthy during Providence's NCAA tournament run and since leaving school has gotten even stronger.
"I've gained 14 pounds since the end of the year, of strength," O'Brien (5-foot-11, 185 pounds) said. "I've never felt this fast or strong. I feel like myself again."
The Flyers were encouraged by what they saw during development camp in June.
"Stepping from high school into the college level, it's a challenge," Flyers assistant general manager Brent Flahr said. "It's not easy. It doesn't matter how good you are. I think he learned that. … He battled through some injuries but hopefully that's behind him. He can put his best foot forward here.
"He's got quick hands, he can really shoot it. His skating is going to be good. He's quick probably more than fast right now, but that's strength-related. In order for him to play against bigger bodies in the NHL, he's going to have to be quick. That's going to be a work in progress."