Llandovery took total control of their match with Coleg Sir Benfro, running in 13 tries in a comprehensive 74-10 win.
Meanwhile, a more competitive affair saw Neath Port Talbot outscore Gower College Swansea by two tries to one in a narrow 12-8 win.
The match can be seen live on the S4C website from 2.30pm and will be repeated in its entirety on the Welsh channel from 10.35pm.
After such a comprehensive win last week, Llandovery will go into the match as favourites although last week's results show that anything can happen. Defending champions Coleg Gwent were somewhat surprisingly beaten by Coleg Morgannwg at the Vale of Glamorgan Hotel and Llandovery head coach Iestyn Thomas knows his side face a tough challenge tomorrow.
"We were surprised with our win last week but it was nice to see us taking our chances," he said.
"I'm expecting a very hard game which will be extremely well contested, particularly up front. They've also got a good set of backs with a few Ospreys academy players in their squad.
"It will be a whole different kettle of fish to last week, it will be a ferociously competitive game."
One of the Ospreys players Thomas will be wary of is Dafydd Howells who is enjoying another promising season and starts at outside centre for Neath Port Talbot. But the Llandovery coach is looking forward to live TV cameras coming down to the college.
"Having the TV cameras down is very exciting and a new experience and hopefully we won't get over excited," he added.
"On paper they're much stronger but we'll see how we go."
In the other remaining matches, Coleg Morgannwg will be looking to continue their winning run when they travel to Coleg Sir Gar in a clash of two other unbeaten sides. Sir Gar started their campaign with a bang as they comfortably beat Bridgend College 45-10 last Wednesday.
Scrum-half Gareth Rees got the scoreboard going and Morgan Griffiths and Craig Woodall added further scores as the home side pulled clear.
Fly-half Jack Maynard added five conversions to a number of second-half scores as Sir Gar registered a comprehensive victory. They will face a tougher test tomorrow though as they take on the team who got one over on the defending champions last week.
Elsewhere, Gower College take on Bridgend College with both sides seeking their first win while Coleg Gwent's clash with Coleg Sir Benfro has been rearranged.