30-year-old Paul McBeth just became the richest player in the sport's history ... inking the massive endorsement deal with Discraft Disc Sports that will pay him a solid 10 milli over the next 10 years.

McBeth is widely considered one of the best disc golfers on the planet -- he has 130 pro wins, 5 world championships and 2 national titles ... and was ranked #1 in the Professional Disc Golf Association rankings before the COVID-19 pandemic hit.

So ... what the heck is disc golf?? It's pretty much like golf, but instead of hitting a ball with a club, you throw a flying disc into a basket made of chains.

It's a sport McBeth has been playing since he was a kid ... and the dude is thrilled to be raking in the dough after decades of hard work.

"It’s mind-blowing to me to think about that 17-year-old me — or even before that, 14-year-old me — made the right move back then to put myself in this position and be able to propel the sport potentially to the next level," McBeth said in a video announcing the deal.

The guy was already making some serious coin via his signature disc line -- he reportedly sold more than 100k of his own discs last year, earning $4 per disc, according to Cypress Point Disc Golf.

McBeth's previous contract with Discraft -- 4 years, $1 million -- was also considered the biggest in the sport at the time ... before he shattered it with the new deal.

McBeth is also married to pro disc golfer in Hannah McBeth, who is a badass in the sport as well with 3 career event wins. The two got married in 2018.