The Wales head coach will be at Llandarcy as home side Neath Port Talbot take on newcomers to the competition, Llandrillo.
With Gatland in attendance and both sides looking to keep tabs on league leaders Coleg Y Cymoedd, there will be plenty to play for with the game streamed live via the S4C website.
“It’s vital we continue to develop the best young Welsh talent at all levels of the game and the Wednesday Under 18 League competition is a vital part of that,” said Gatland.
“It gives young players the chance to play competitive mid-week rugby to a high standard alongside the Regional Age Grade Championship.
“Some of these players will then move on to play for Wales Under 18 but as a whole, the competition can only benefit all the players and coaches involved.”
In their debut season, Coleg Llandrillo have impressed with full back Morgan Williams a standout at full back.
“It’s half term so we haven’t seen much of the boys but we finished well last week with a win over Coleg Gwent,” said Llandrillo head coach Josh Leach.
“That was a big positive as they had beaten us a few weeks ago. It shows how far we’ve come as a team and we’re building momentum now both in training and in games. There is a lot of continuity in our squad though we try not to focus too much on the game being on TV.”
Neath Port Talbot College Director of Rugby Max Howells, who is still without captain Adam Beard and No. 8 Josh Middleton, said: “Our first half performance against Cymoedd last week was dreadful but we improved and we’ll take the second half as a positive.
“Llandrillo have done very well this season and you can’t under estimate anyone in this league. We certainly won’t do that on Wednesday.”
In the other games to take place this week, leaders Coleg Y Cymoedd host Bridgend College while Coleg Sir Gar will hope to bounce back from consecutive defeats when they host Coleg Gwent.
There are two fixtures in the Trophy competition with Cowbridge Comprehensive hosting Newport High School and Llandovery College travelling to Tenby to meet Pembrokeshire Schools.
WRU Wednesday Under 18 League fixtures: 30/10/13.
Coleg Y Cymoedd vs. Bridgend College (Taffs Well RFC KO 2.30)
Neath Port Talbot College vs. Coleg Llandrillo (Llandarcy KO 2.30. Live via http://www.s4c.co.uk/rygbi/)
Coleg Sir Gar vs. Coleg Gwent (Coleg Sir Gar KO 2.00)
Cowbridge Comprehensive vs. Newport High School (Cowbridge Comprehensive KO 12.00)
Pembrokeshire Schools vs. Llandovery College (Tenby RFC KO 2.30)
