The return of Williams, Anscombe, Beard, Rowlands and Wainwright provides 234 caps and gives some much-needed experience to the side that played against Australia.
In all, Gatland has made seven personnel changes from the side that lost to the Wallabies in the second Test in Melbourne in July, with three more positional alterations.
Wales have lost their past nine internationals in a run that stretches back 13 months and have slipped to 11th in the world rankings, one place below Fiji.
Another defeat will equal Wales’ record of 10 successive international defeats, set by Steve Hansen’s side of 2002 and 2003.
Wales open their autumn campaign against Fiji before facing Australia seven days later and finish with the visit of world champions South Africa on 23 November.
“We know how dangerous Fiji can be, so we’ve got to make sure that we bring physicality and are ruthless on Sunday,” said Gatland.
“We need to be switched on for the full 80 minutes.”
