All three adjustments are made in the forwards where hooker and vice captain Stuart McInally, No 8 Magnus Bradbury, and second row Sam Skinner all start.
Glasgow pair Fraser Brown and Scott Cummings move to the bench as a consequence with their fellow Warrior Matt Fagerson coming into the match day squad.
Townsend has named the same back division for a third Test in a row with half-backs Ali Price and Adam Hastings inside centre pairing Sam Johnson and Chris Harris.
Captain Stuart Hogg and wings Blair Kinghorn and Sean Maitland make up the back three.
Maitland is now ninth in Scotland’s all-time top try-scorers after his brace in the win over France last weekend.
Hogg will move into joint seventh place on Scotland’s all-time appearance list in Cardiff overtaking recently retired former skippers Greig Laidlaw and John Barclay to join Jason White and Nathan Hines on 77 caps.
Townsend said: “We set out this season to improve our consistency over a run of five tough games, something we have done well so far.
“We’ve stayed in the fight in every game which is a credit to how hard the players have worked in training and during the Tests.
“It’s also been encouraging to see how well the players have grown together and have taken on board the input from new coaches Steve Tandy and Pieter de Villiers who have done a great job in their first season with the team.
“We’ve still got a lot to improve on and we’ll have to fight even harder on Saturday in Cardiff which is one of the best and toughest places to play Test rugby.”
Townsend added: “We have huge respect for the Welsh team who narrowly missed out on a World Cup final a few months ago. They are well coached and have some outstanding players.
“It will be a fantastic occasion and one last opportunity to play to our potential in this championship.”
Scotland team to face Wales: Stuart Hogg; Sean Maitland, Chris Harris, Sam Johnson, Blair Kinghorn; Adam Hastings, Ali Price; Rory Sutherland, Stuart McInally, Zander Fagerson, Sam Skinner, Grant Gilchrist, Jamie Ritchie, Hamish Watson, Magnus Bradbury
Substitutes: Fraser Brown, Allan Dell, Willem Nel, Scott Cummings, Matt Fagerson, George Horne, Duncan Weir, Kyle Steyn
