Their roles were confirmed after they each successfully came through training at the University of Glamorgan today.
Ioane's return at centre in place of Ryan Cross is one of three changes to the Australian starting XV from that which took the field in the Hopetoun Cup Test match. The others see flanker David Pocock and lock Dean Mumm gain starts, for George Smith and Mark Chisholm respectively.
Pocock was rested last weekend against Scotland, after being heavily involved earlier in the tour, while Mumm has been rewarded for his all-round efforts.
As well as being a member of the Test match squad through the trip, the NSW Waratahs second rower also led the midweek Australian XV to victories over firstly Gloucester, and then Cardiff earlier this week.
Both Smith and Chisholm have been included on the bench, as has NSW Waratahs utility back Kurtley Beale and Western Force prop Matt Dunning.
Beale, who will make his debut if called onto the field, scored two tries from the unfamiliar wing position during Tuesday night's 31-3 win over Cardiff. He offers additional cover at flyhalf, inside centre, wing and fullback.
Cross, loose forward Richard Brown and prop Sekope Kepu have all been omitted after featuring in last week's match night squad.
Qantas Wallabies coach Robbie Deans says the recovery of the injured quartet is a big boost for his side as it bids to finish a demanding year strongly.
"They're all, in their own right, influential players, both in terms of their actions and the impact that they have on their mates around them, so it is good to have them all back on deck," Deans says.
"No one was more disappointed than us, in terms of the way our most recent Test outing turned out. It was an incredibly frustrating night for everyone involved, as it no doubt was for everyone who was watching back home. We can't alter that outcome now but we're not dwelling on it either. We will learn the lessons from that experience and move on. As a group, we are fortunate that we have another opportunity, so that we can attempt to end this tour, and the year, on a more positive note."
Scotland's 9-8 win last weekend has denied the Wallabies an opportunity to complete the European leg of their expedition unbeaten.
In Wales, they now face an opponent that edged out last year's tourists 21-18, to secure the James Bevan Trophy for the first time.
"This match is a big test of our collective character as a group, there's no doubt about that," Deans says.
"As they showed when we visited last year, and in the recent home matches that they've had against South Africa and the All Blacks, the Welsh are a formidable opponent. They've consistently been one of the best teams in Europe during the last two years, have an experienced playing roster, and had a wide representation on the British Lions tour earlier in the year."
Wales approaches the final game of its November series confident after piecing together successive victories over Samoa and Argentina following a first-up 12-19 defeat by New Zealand.
Just six of the players named in Qantas Wallabies starting line-up announced today were also in the run on side 12 months ago, when Wales beat Australia.
Those players are Ioane, Drew Mitchell, Peter Hynes, Matt Giteau, Stephen Moore and Benn Robinson. Mitchell (who played fullback) and Ioane (wing) are in different positions a year on.
Saturday represents the Wallabies' 14th and final Test of the year, with the majority of the team returning to Australia on Sunday night.
The Qantas Wallabies, is:
15. Adam Ashley-Cooper (Brumbies)
14. Peter Hynes (Queensland Reds)
13. Digby Ioane (Queensland Reds)
12. Quade Cooper (Queensland Reds)
11. Drew Mitchell (NSW Waratahs)
10. Matt Giteau (Brumbies)
9. Will Genia (Queensland Reds)
8. Wycliff Palu (NSW Waratahs)
7. David Pocock (Western Force)
6. Rocky Elsom (Brumbies, captain)
5. Dean Mumm (NSW Waratahs)
4. James Horwill (Queensland Reds)
3. Ben Alexander (Brumbies)
2. Stephen Moore (Brumbies)
1. Benn Robinson (NSW Waratahs)
16. Tatafu Polota-Nau (NSW Waratahs)
17. Matt Dunning (Western Force)
18. Mark Chisholm (Brumbies)
19. George Smith (Brumbies)
20. Luke Burgess (NSW Waratahs)
21. James O'Connor (Western Force)
22. Kurtley Beale (NSW Waratahs)