Mike McCarthy, who impressed for Ireland during the recent GUINNESS Series, makes a welcome return to the second row where he partners Michael Kearney.
It will be the 21-year-old Kearney's first Heineken Cup start after he made three appearances off the bench against Gloucester (twice) and Toulouse last season.
Heineken Cup debutant Andrew Browne moves to blindside flanker and is joined in a youthful back row by Willie Faloon and Eoin McKeon, who on Friday will earn his 20th Connacht cap.
Fetu'u Vainkolo replaces hamstring injury victim Gavin Duffy on the left wing, with South African Danie Poolman making his European bow at outside centre.
There are no further changes to the back-line with Dan Parks captaining the side for the eagerly-anticipated Pool 3 clash.
Hooker Ethienne Reynecke has recovered from injury to take his place on the bench. He joins Denis Buckley and JP Conney as the front row replacements.
Connacht stalwart Swift is disappointed to be missing out on the occasion but is also looking forward to enjoying the atmosphere from the sidelines.
"Obviously I'm disappointed not to be playing, but this game means as much to me as if I was out there on the pitch. And I can't wait to get behind the boys in one of the biggest games in Connacht's history," said the province's most-capped player.
"Last year was unbelievable with the atmosphere the competition generated around the province and the home crowd were incredible each game. The supporters have been amazing all season and we need that support again this week.
"Biarritz are a challenging side but we know what to expect and I have every confidence that the lads will do us proud and that we can win this one."
While the Main Stand and Clan Stand are now sold out, there are still tickets available in the stands erected at both ends of the Sportsground. These tickets are €30 for adults and can be purchased from the Connacht Branch or online here.
CONNACHT (v Biarritz Olympique): Robbie Henshaw; Tiernan O'Halloran, Danie Poolman, David McSharry, Fetu'u Vainikolo; Dan Parks (capt), Kieran Marmion; Brett Wilkinson, Jason Harris-Wright, Ronan Loughney, Michael Kearney, Mike McCarthy, Andrew Browne, Willie Faloon, Eoin McKeon.
Replacements: Ethienne Reynecke, Denis Buckley, JP Cooney, Daniel Qualter, Johnny O'Connor, Paul O'Donohoe, Miah Nikora, Matthew Jarvis.