Danny Wilson racked up back-to-back victories in the opening two round of the European Challenge Cup pool stage, brushing aside Top 14 leaders, Lyon, at Cardiff Arms Park before claiming a historic victory at Stade Toulousain’s Stade Ernest Wallon.
The Blues hope to move above Zebre into fourth position in Conference A, while the Scarlets, who suffered a 13-18 loss to a Rhys Priestland-inspired Bath at Parc y Scarlets last week, will be looking to maintain their place at the top of Conference B, despite pressure from Ulster and Leinster.
Wilson has made five changes to the side that won in south of France last week, as Willis Halaholo returns to link-up with Rey Lee-Lo in midfield.
Elsewhere, Brad Thyer, Dillon Lewis, Seb Davies and Olly Robinson all come into the pack, while Kristian Dacey remains captain.
Matthew Rees, Keiron Assiratti, Josh Turnbull and Rhun Williams also come into the match day 23 and are named on the bench.
Scarlets, meanwhile, introduce Scott Williams back into the centre to partner Hadleigh Parkes, and the Welsh international is named captain for the derby clash.
The backline also includes Cardiff Blues products Leigh Halfpenny and Rhys Patchell, while British and Irish Lions star, Jonathan Davies, is named amongst the replacements.
Further changes are made to the front row, with Ryan Elias and Werner Kruger replacing internationals Ken Owens and Samson Lee respectively.
What They Said
Josh Navidi is expecting a tough challenge in Llanelli, and is looking forward to the opportunity to back up last week's win in France.
"In the changing rooms afterwards the boys were buzzing - a win out there doesn't come around that often.
"I remember a few years ago when we won out in France with Richie Rees and a couple of the other boys playing. When they came back to base you could see the attitude and drive, it changed the persona in the environment.
"We have built through with a good couple of wins and now it is about backing it up against the Scarlets.
"It's a tough place to go bit it's one you have to get on with. It's a local derby and there's always an edge around it - the boys are looking forward to it and I'm sure as we get closer there will be more pressure building."
Scarlets: Leigh Halfpenny; Johnny Mcnicholl, Hadleigh Parkes, Scott Williams (capt), Steff Evans; Rhys Patchell, Gareth Davies; Wyn Jones, Ryan Elias, Werner Kruger, Jake Ball, Lewis Rawlins, Aaron Shingler, Will Boyde, Tadhg Beirne
Replacements: Ken Owens, Dylan Evans, Simon Gardiner, David Bulbring, Josh Macleod, Jonathan Evans, Paul Asquith, Jonathan Davies
Cardiff Blues: Matthew Morgan; Alex Cuthbert, Rey Lee-Lo, Willis Halaholo, Blaine Scully; Jarrod Evans, Tomos Williams; Brad Thyer, Kristian Dacey (capt), Dillon Lewis, Seb Davies, James Down, Josh Navidi, Olly Robinson, Nick Williams.
Replacements: Matthew Rees, Corey Domachowski, Keiron Assiratti, Macauley Cook, Josh Turnbull, Lloyd Williams, Steve Shingler, Rhun Williams.