Royal Birkdale has been lengthened by 154 yards, with 20 new hazards added, in preparation for the 2008 Open.
A new green has also been built at the 17th, along with six new tees. The new hazards include 16 fairway bunkers. The layout now totals around 7,122 yards.
Peter Dawson, chief executive of Open organisers the R&A, said Royal Birkdale had always been a strong Open venue.
"We feel that by introducing these changes, its challenge can be maintained," he added.
"We have paid particular attention to the introduction of tee shots that give players a number of strategic options.
"Through tighter bunkering and the recontouring of green surrounds, we intend to make players execute more imaginative recovery shots around the greens."