Williams claimed one of the seven tries as Wales bounced back from an 18-17 defeat by Scotland in their opening fixture and have now set up a match against Georgia on Saturday.
Captain and full-back Dafydd Howells scored a hat-trick of tries, with the rest coming from Josh Adams, Dan Jones, Torin Myhill and Williams. Dan Jones slotted four conversions, with Luke Price also adding a kick.
Wales Under-18s: Dafydd Howells (Ospreys) (c); Josh Adams (Scarlets), Garyn Smith (Blues), Tyler Morgan (Dragons) (Joe Thomas Ospreys 40), Rhys Williams (Leicester Tigers); Daniel Jones (Scarlets) (Luke Price Ospreys 41), Tom Williams (Blues) (Daniel Brooks Ospreys 41); Keagan Bale (Dragons) (Robert Lewis Blues 41), Ryan Elias (Scarlets) (Torin Myhill Scarlets 41), Dillon Lewis (Blues) (Alex Jeffries Dragons 41), Gareth Allen (Dragons) (Adam Williams, Ospreys, 55), Rory Thornton (Ospreys), Tom Phillips (Scarlets), Matthew Marley (Blues), Jonathon Fox (Ospreys)
