Hundreds of athletes are coming to Tulsa to compete in Ironman races on Sunday.

It's the last time for Ironman to be hosted in Tulsa. Around 1,300 athletes will compete in the races on Sunday that will take them throughout Green Country. Triathletes are gearing up to swim more than a mile, bike for 112 miles, and then run 26.2 miles, a full marathon.

This is the third and final Ironman race in Tulsa, and this year, there's also a half-race. It's Ross Harper's ninth Ironman to compete in and his first one on the U.S. mainland. He traveled to Tulsa from his hometown in England.

"It was meant to be one and done, like many people. And as soon as you cross that finish line, you want to do it again. It's a legal high, as they would say,” Harper said.

Harper says he trains around his full-time job and focuses on intensity for the last few months leading up to the race day. He says there's no feeling like crossing the finish line.

"It's hard to describe. It's kind of a bit different every time, it depends on whether you've maybe gone faster than you've gone before. Or if you've had the race you sort of wanted to have. But even if you've not had a great day or if you've had an amazing day, the moment you hit that red carpet and it's all over, you can grab a beer and see your family properly and stuff. Yeah, there's just nothing like it,” Harper said.

On Sunday morning, athletes will swim in Keystone Lake, then bike through Green Country, and run through the city of Tulsa.