Limited tickets are still available for the encounter, as Danny Wilson's side look to book a place in May's final at Bilbao.
The winner of Saturday's clash will meet the winner of tonight's match, between Gloucester and Newcastle Falcons, at San Mamés Stadium, the home of La Liga giants, Athletic Bilbao, on May 11.
The game will be another chapter of the Blues' rich history in Europe, which includes lifting the Challenge Cup trophy following the 2010 victory over a star-studded Toulon in Marseille.
Leading the side eight years ago was Gethin Jenkins, who returns from a short-term injury to captain Wales' Capital Region again on Saturday.
Wales' record cap holder is joined in a new-look front row by Kristian Dacey and Anton Peikrishvili. International hooker, Dacey, also recovers from a niggle which kept him out of the recent trip to South Africa.
There are a number of intriguing match-ups across the pitch, including at centre, as the in-form partnership of Rey Lee-Lo and Willis Halaholo take on Jale Vatubua and 94-times capped All Black international, Conrad Smith.
There will also be plenty of eyes on the look-out for the back row battle, as Pau have Wallabies international, Ben Mowen and former European Player of the Year, Steffon Armitage, in their ranks. Meanwhile, the home side have named Nick Williams and Welsh internationals Josh Navidi and Ellis Jenkins at the base of their pack.
Cardiff Blues' young outside half, Jarrod Evans, who has been heavily influential throughout the season, has another exciting challenge ahead, as he is named opposite All Blacks international, Tom Taylor.
There will be a host of emotional farwells at the Welsh capital, as the game signals the end of Danny Wilson, Matt Sherratt, Alex Cuthbert and Taufa'ao Filise's times at the region.
What They Said
Danny Wilson insists Saturday's Challenge Cup semi final against Pau is a "massive opportunity" for the entire Cardiff Blues region, as they look to book a place in May's final in Bilbao.
Following a recent run of impressive form, the Cardiff Blues head coach believes his side can be confident heading into the encounter, but is well aware of the strength that Simon Mannix's side possess.
"For us as a group, and for the region as a whole, it's a massive opportunity to go and have a big day out in an European final, which we're all extremely motivated by," said Wilson.
"Now we have a chance to do something special, but we won't get ahead of ourselves.
"The opposition we're facing is a very strong one but we're at the Arms Park, hopefully a packed-out Arms Park, with a derby feel about it and those are the days and occasions that we want to be part of.
"It's a good side and a star-studded side, but our form over the last three months has been right up there and hopefully we can keep that going on Saturday.
"There will be a big atmosphere, a lot of nerves and both sides will be looking to bring the physicality that you need early on to set the tone. That physical battle will have a major part in who can get over the line and get the win."
The encounter is set to be a special occasion at the iconic Cardiff Arms Park, according to captain, Gethin Jenkins.
Jenkins is as hungry as ever for success with the region, and believes his side can head into Saturday's clash with confidence, having impressed with their home form throughout the campaign.
"It's always nice to lead the boys out at the Arms Park. It will be a good feeling for myself to get out onto that pitch and hopefully lead the team to a final," said Jenkins.
"Every time we've played there this season we've looked to build and build and put in performances that people can be proud of. We'll look to continue that on the weekend.
"The big challenge for us was going away to Edinburgh. We knew that the result of that would be a nice, home semi final so everything will be focused on putting thing into place so we can get a good performance and hopefully get the victory.
"It's probably a little bit different to usual because we're home, at the Arms Park, and I've never played a home semi final there before.
"It should make for a great atmosphere and the boys are really looking forward to getting out on our home patch and giving a good performance.
"Pau have got a lot of experience in their squad. We're aware of how well they've been doing in the French league and some of the performances they've put in.
"They've got quality throughout with ex-All Blacks and Steffon Armitage, who is a key player for them, and some senior forwards, who have been around the block, making for a strong pack."