Wales recorded a Six Nations try bonus point in the first half for the first time on their way to their largest win against Ireland this century.
Captain Nichola Fryday's 66th-minute try was part of an improved second half showing from Ireland, yet they were second best in all facets of play during the opening 40 minutes as Wales bossed the collisions.
Backed by a strong wind and the vocal Cardiff support, Ioan Cunningham's side whipped up huge momentum from their dominant set-piece play. Young player-of-the-match Sisilia Tuipulotu starred in that regard.
Alex Callender, director-in-chief Keira Bevan, replacement Sioned Harries and captain Hannah Jones all crossed to seal the bonus point by the 32nd minute, leaving Ireland 26 points adrift at half-time.
It was certainly a baptism of fire for teenage prop Sadhbh McGrath on her Ireland debut, while injuries to Sam Monaghan, who had to go off briefly, and Méabh Deely also had an impact.
Looking slightly shellshocked at times, Ireland regrouped and replacement Deirbhile Nic a Bháird was a livewire and lifted her team-mates, albeit that her yellow card preceded a close-range try from Tuipulotu.
Although well beaten in the end, Greg McWilliams' charges evened up the contest in some notable areas, including the scrum where Niamh O'Dowd, on her debut, and fellow replacement Christy Haney did well off the bench.
Ireland were stung by an early unconverted try as powerful young prop Tuipulotu forced a scrum penalty, setting up a surging third-minute maul that landed flanker Callender over the line in the left corner.
The visitors responded with some ground-gaining carries, but Wales looked the sharper outfit. Scrum half Bevan sniped in under the posts and converted for a 12-0 lead.
With Ireland unable to get out of their own half, Wales exerted more pressure off a bustling Hannah Jones carry. Enya Breen was slow to roll away and with the penalty tucked away to touch, Harries was driven over for try number three, converted by Bevan.
Ireland's scrummaging improved, with newcomer McGrath gaining confidence from a penalty win, but by that stage Wales already had their bonus point. Kerin Lake handed off Nicole Cronin to release her centre partner Jones who burst in under the posts, putting 26 points between the teams.
The girls in green avoided an initial second half concession, with tighthead Tuipulotu denied by a knock-on highlighted by TMO Ian Tempest. However, the newly-introduced Nic a Bháird soon saw yellow for what was deemed a deliberate knock-on.
There was no denying 19-year-old powerhouse Tuipulotu a second time, as she absorbed three attempted tackles and grounded the ball despite the best efforts of Aoife Dalton.
Winger Aoife Doyle's departure at 31-0 down saw Dannah O'Brien make her first Six Nations appearance, slotting in at out-half with Cronin moving to scrum half and Molly Scuffil-McCabe reverting to the wing.
Ireland finally had some go-forward ball to work with, pressing from a maul and with O'Brien connecting with her offloads. Scuffil-McCabe also got a chance to stretch her legs out wide, and better defence saw Cronin and Dalton both win penalties at the breakdown.
Nic a Bháird typified the renewed Irish urgency, lifting the tempo with quickly-taken penalties and pacy carries. Wales were pushed right back to their own line and Fryday was able to crash over, with TMO confirmation of the score.
O'Brien flicked the conversion wide and there were no further scoring opportunities, Wales managing to steal a lineout and also bundle Dalton into touch as they opened the Championship with a convincing five-try victory at the Arms Park.
TIME LINE: 3 minutes - Wales try: Alex Callender - 5-0; conversion: missed by Keira Bevan - 5-0; 12 mins - Wales try: Keira Bevan - 10-0; conversion: Keira Bevan - 12-0; 22 mins - Wales try: Sioned Harries - 17-0; conversion: Keira Bevan - 19-0; 32 mins - Wales try: Hannah Jones - 24-0; conversion: Keira Bevan - 26-0; Half-time - Wales 26 Ireland 0; 44 mins - Ireland yellow card: Deirbhile Nic a Bháird; 45 mins - Wales try: Sisilia Tuipulotu - 31-0; conversion: missed by Keira Bevan - 31-0; 66 mins - Ireland try: Nichola Fryday - 31-5; conversion: missed by Dannah O'Brien - 31-5; Full-time - Wales 31 Ireland 5
WALES: Courtney Keight (Bristol Bears); Lisa Neumann (Gloucester-Hartpury), Hannah Jones (Gloucester-Hartpury) (capt), Kerin Lake (Gloucester-Hartpury), Carys Williams-Morris (Loughborough Lightning); Elinor Snowsill (Bristol Bears), Keira Bevan (Bristol Bears); Gwenllian Pyrs (Bristol Bears), Kelsey Jones (Gloucester-Hartpury), Sisilia Tuipulotu (Gloucester-Hartpury), Abbie Fleming (Exeter Chiefs), Gwen Crabb (Gloucester-Hartpury), Georgia Evans (Saracens), Alex Callender (University of Worcester Warriors), Bethan Lewis (Gloucester-Hartpury).
Replacements used: Sioned Harries (University of Worcester Warriors) for Crabb (6 mins), Kate Williams (Unattached) for Lewis (56), Cerys Hale (Gloucester-Hartpury) for Tuipulotu, Hannah Bluck (University of Worcester Warriors) for H Jones, Ffion Lewis (University of Worcester Warriors) for Bevan (all 60), Kat Evans (Saracens) for K Jones (62), Caryl Thomas (University of Worcester Warriors) for Pyrs (71). Not used: Lleucu George (Gloucester-Hartpury).
IRELAND: Méabh Deely (Blackrock College RFC/Connacht); Aoife Doyle (Railway Union RFC/Munster), Aoife Dalton (Old Belvedere RFC/Leinster), Enya Breen (Blackrock College RFC/Munster), Natasja Behan (Blackrock College RFC/Leinster); Nicole Cronin (UL Bohemian RFC/Munster), Molly Scuffil-McCabe (Railway Union RFC/Leinster); Sadhbh McGrath (City of Derry RFC/Cooke RFC/Ulster), Neve Jones (Gloucester-Hartpury/Ulster), Linda Djougang (Old Belvedere RFC/Leinster), Nichola Fryday (Exeter Chiefs/Connacht) (capt), Sam Monaghan (Gloucester-Hartpury/IQ Rugby), Dorothy Wall (Blackrock College RFC/Munster), Maeve Óg O'Leary (Blackrock College RFC/Munster), Brittany Hogan (Old Belvedere RFC/Ulster).
Replacements used: Hannah O'Connor (Blackrock College RFC/Leinster) for Monaghan (19-31 mins), Vicky Irwin (Sale Sharks/Ulster) for Deely (31), Deirbhile Nic a Bháird (Old Belvedere RFC/Munster) for O'Leary (half-time), Dannah O'Brien (Old Belvedere RFC/Leinster) for Doyle (47), Christy Haney (Blackrock College RFC/Leinster) for McGrath, Jo Brown (University of Worcester Warriors/IQ Rugby) for Wall, Grace Moore (Saracens/IQ Rugby) for Hogan (all 56), O'Connor for Cronin (63), Niamh O'Dowd (Old Belvedere RFC/Leinster) for Djougang (71).
Referee: Amber McLachlan (Australia)