With each team unbeaten, Wednesday's clash will see something give in what looks sure to be an entertaining encounter on the artificial surface.
Elsewhere, there are two other fixtures taking place in the Cup competition. Coleg Gwent hosting Neath Port Talbot College at Waunfawr Park while Bridgend College face the long trip north to face Llandrillo College at Parc Eirias.
In the WRU Wednesday Under 18 Trophy, Cowbridge Comprehensive have a second home tie in successive weeks, this time against Pembrokeshire Schools and Gower College meet Llandovery College.
Looking ahead to their clash with Cymoedd, Sir Gar head coach Euros Evans is confident his side can get another win in a game which is a rerun of last year's final.
"It's going to be a big challenge. Cymoedd have had a really good start and hit the ground running," he said.
"They will be a real test to see where we are as a team but the boys are really looking forward to playing at the Arms Park. Obviously it's a stadium with a great deal of history and now it's a lot more modern with the new artificial surface.
"It should make for a real open and attacking game. Hopefully the weather will hold off and allow both sides to play as I'm sure that's the intention. We're two evenly matched teams and although we've got a couple of long term injuries, we're more than capable of getting the win."
Sir Gar will face a strong Cymoedd side with plenty of power up front. Liam Belcher, who has featured in the Pontypridd squad this season, starts at hooker alongside Robert Lewis and Kieran Assaratti in the front row. Hemi Barnes at No. 8 and fly Jared Evans provide plenty of experience after featuring in the competition last year.
"It should be an exciting encounter and looking at both sides, there are some top players on show," said Cymoedd Director of Rugby Clive Jones.
"We'll look to play some rugby so I'm sure there'll be plenty of entertainment for the TV viewers."
The clash between Coleg Sir Gar and Coleg Y Cymoedd can be seen live via the S4C website at 2.30pm.