Jameis Winston and his girlfriend Breion took the plunge ... sorta ... at a spiritual retreat in Colorado this week, surrounded by a BUNCH of NFL stars.
No, we're not talkin' marriage ... but they did get baptized together at a Pro Athletes Outreach event in Colorado Springs -- an annual event that brings together hundreds of NFLers every year.
The event is geared toward couples -- who pray together, attend workshops together and listen to different religious and motivational speakers.
Among the stars this year ... Antonio Cromartie and Brian Hartline ... and Kurt Warner ran a seminar.
We're told the organization was founded by NFL players 45 years ago -- though athletes from other sports like baseball and basketball often attend events as well.