Wales start the championship challenge against Samoa on 5 June
Newport Gwent Dragons' Dan Watchurst will skipper Wales at the Junior World Championship in Argentina in June.
Watchurst, 20, will head a three-man leadership team alongside Cardiff Blues academy's Rhys Downes and Josh Navidi.
Wales Under-20 head coach Phil Davies gave the three players equal chance of captaincy in the recent Six Nations.
"The group stood up very well in the Six Nations with all three of these players managing the side with great enthusiasm and maturity," said Davies.
After captaining the Wales side in the first two of the Six Nations games, prop Watchurst will have full captaincy when they travel to Argentina in June.
Scrum-half Downes, 20, and flanker Navidi, 19, will go as vice-captains.
No uncapped players are named and only two players did not feature in the recent Six Nations - Adam Hughes was injured, while Ashley Beck was playing for the Ospreys.
Davies added, "The selection of Ashley and Adam will benefit the players themselves in their rugby development and provide additional professional experience to the squad, with both players having represented their region on a number of occasions this season.
"The Junior World Championship is now a 12-team tournament so every game will be tough. We have a very physical pool with three southern hemisphere teams who we don't come up against very often, but it will be a great challenge for the players, providing invaluable experience for their future rugby careers.
"We play England in a warm-up game next Thursday at Cross Keys as part of our aim to play the best teams in the world as often as possible."
Wales Under-20 squad for IRB Junior World Championship (Argentina, June 5 - 21):
Forwards: Dan Watchurst (Dragons academy / Bedwas), Simon Gardiner (Scarlets academy / Carmarthen Quins), Joe Rees (Tonmawr), Rhodri Jones (Scarlets academy / Llandovery), Rhys Williams (Blues academy / Pontypridd), Ieuan Davies (Glamorgan Wanderers), James King (Ospreys academy / Aberavon), Macauley Cook (Blues academy / Pontypridd), Lloyd Peers (Ospreys academy / Bridgend), James Thomas (Dragons academy / Ebbw Vale), Josh Navidi (Blues academy / Glamorgan Wanderers), Rhys Jenkins (Dragons academy / Ebbw Vale), Toby Faletau (Dragons academy / Cross Keys), Morgan Allen (Pontypool)
Backs: Rhys Downes (Blues academy / Pontypridd), Gareth Davies (Scarlets academy / Llanelli), Matthew Jarvis (Ospreys / Aberavon), Steven Shingler (Llanelli / Llangennech), Ashley Beck (Ospreys / Aberavon), Scott Williams (Scarlets academy / Llanelli), Owen Williams (Blues academy / Cardiff), Ben John (Ospreys academy / Aberavon), Adam Hughes (Dragons academy / Newport), James Loxton (Blues academy / Cardiff), Kristian Phillips (Ospreys academy / Neath), Dan Fish (Blues academy / Glamorgan Wanderers)