Kiwi prop Craig Dunlea takes over from countryman Deacon Manu in the front row as Director of Rugby Phil Davies keeps faith with the majority of the side that won 35-11 at Ulster.
Davies said: "We want continuity with our performance and our team selection. We have avoided making big changes.
"We were very pleased to qualify for the quarter-finals and the key now is to win the last Pool game and hopefully secure home advantage in the next round."
Llanelli Scarlets: M Stoddart; D James, R King, G Evans, M Watkins; S Jones, D Peel; I Thomas, M Rees, C Dunlea, A Jones, S Macleod, S Easterby (capt), G Thomas, A Popham
Replacements: K Owens, D Manu, V Cooper, D Jones, C Stuart-Smith, C Thomas, D Daniel
London Irish: Team selection not available at present