England headed into the match at Eugene Cross Park on the back of wins over Italy, Japan High Schools and Scotland (twice), and it was their final match before they go on a development tour this summer.
Captain and No.8 Alex Gray led the way with his first try for England U18s, and fly half George Ford was on top form with two tries, four conversions and a penalty for 21 points. And England made light of losing brothers Billy and Mako Vunipola to the sin bin within a minute of each other late in the second half, conceding only one try while they were down to 13 men.
England U18 coach John Fletcher said: "It was a tough fought-out win but we are pleased to score five tries away to Wales. At times we played very well, and created other opportunities which we might have taken on another day. Wales started quite well and had a bit of territory but in a few minutes either side of half-time we scored the majority of our tries and played impressively.
"We know as a team we can play better but the business we're in is all about the players and they have come on well and won five matches out of five."
Wales had defeated France, 27-15 in Soissons, and 29-6 victory over Italy in Aberavon, followed by two matches staged in Italy: a 25-22 defeat to Ireland and a 23-13 win over Scotland.
But England started well when Gray went over after nine minutes and, following a Wales penalty by full back Tom Prydie, the white jerseys were in again in the 25th minute when Ford found a gap after a lineout and passed to the scorer, Matt Everard.
Ford converted that one and did so again when, just before half-time, the fly half's grubber kick after a short driving maul off a lineout was seized on by centre Jonathan Joseph and England led 19-3.
Ford and Prydie exchanged penalty goals in the first three minutes of the second half, then Ford nipped over at the posts and converted to extend England's lead to 29-6. Prydie put over his third penalty then, after 44 minutes of the 35 minutes each-way match, Ford crossed again following a scrum and converted for 36-9.
Replacement Dale Ford grabbed Wales's solitary try, converted by Prydie, and with 29 minutes of the second half gone Billy Vunipola - just on as a replacement for flanker Everard - went to the sin bin, followed almost straight away by his older brother Mako, the prop. But England stuck to their task and allowed Wales only a converted try to make the final score 36-23 in the visitors' favour.
England U18: Jack Wallace (London Wasps and RGH High Wycombe); Marcus Watson (London Irish and St George's College), Jonathan Joseph (London Irish and Millfield School), Owen Farrell (Saracens and St George's School), Manu Tuilagi (Leicester Tigers and John Cleveland College); George Ford (Leicester Tigers and Rishworth School), Ryan Glynn (Sale Sharks and Sedbergh School); Mako Vunipola (Bristol Rugby and Millfield School), Harry Allen (Saracens and Chislehurst & Sidcup Grammar), Ryan Bower (Leicester Tigers and John Cleveland College), Sam Twomey (Harlequins and Dulwich College), Charlie Matthews (Harlequins and Hurstpierpoint College), Joe Trayfoot (Harlequins and Epsom College), Matt Everard (Leicester Tigers and Wyggeston & Queen Elizabeth I College), Alex Gray (Newcastle Falcons and Barnard Castle School, capt). Replacements: Henry Thomas (Bristol Rugby and Millfield School) for Bower 47, Peter Austin (London Irish and St Paul's Catholic College) for Allen 41, Billy Vunipola (Bristol Rugby and Castle School) for Everard 62, Sam Jones (London Wasps and Aylesbury Grammar) for Trayfoot h-t, Andy Short (Worcester Warriors and Worcester 6th Form College) for Joseph 58, Christian Wade (London Wasps and RGS High Wycombe) for Watson 39. Not used: Rob Buchanan (Harlequins and St Bede's School), Sam Stuart (Harlequins and Sedbergh School), Jake Sharp (Saracens and Oaklands College), Sam Edgerley (London Irish and Wellington College).
England U18s Five Nations Festival Squad Playing Schedule
March 22, Kingston Park, England v Scotland, WON 63-0
March 29, Sandy Park, England v Japan High Schools, WON 71-7
April 12, Stadio L.Zaffanella, England v Italy, WON 61-3
April 15, Stadio L.Zaffanella, England v Scotland, WON 75-0
April 26, Eugene Cross Park, England v Wales, WON 36-23.