Wales continued to dominate in the second half and there was no way back for the Irish when Tom Shanklin's straight break and pass enabled full-back Kevin Morgan to plunge over.
Ireland rallied with tries from Marcus Horan and Geordan Murphy but Wales never looked in danger of losing and their fans were singing long before the final whistle sounded.
When Wales were penalised for jumping across at the ensuing line-out, Ronan O'Gara drew first blood with a third-minute penalty which sailed between the uprights.
Brian O'Driscoll looked to be in trouble in the 10th minute for palming Brent Cockbain in the face and then appearing to stamp on the Ospreys lock, who was attempting to get up.
Referee Chris White failed to spot the incident which went unpunished, but outraged Welsh fans soon turned their minds to other matters as Gavin Henson slotted a drop goal.
Wales went ahead lead in the 16th minute when an O'Gara clearance was charged down by prop Jenkins who fly-hacked forward and fell on the ball when it crossed the line. Jones converted.
When Henson rifled over a penalty from the halfway line Wales led 13-3 but Ireland hit back. A stunning move in the 24th minute carved Wales wide open with O'Driscoll releasing winger Denis Hickie. He fed Geordan Murphy who in turn found Girvan Dempsey but Stephen Jones and Mark Taylor covered to make a superb double tackle, holding the Leinster winger up over the line.
Ireland had the put-in at the scrum but despite Shane Byrne hooking the ball, it found its way on to the Wales' side as the home team claimed a crucial turnover.
Jones potted his second penalty to increase the lead to 16-3 shortly afterwards when O'Driscoll came into a ruck from the side.
A late tackle on O'Driscoll gave O'Gara a chance to reduce the deficit and he gratefully accepted but Wales led 16-6 at half-time, a lead they were not to relinquish.