Coverage of the Wales v Argentina game starts on S4C at 16.50 as the channel builds up to kick off.
S4C will also be screening the final of the tournament live with each match also available to watch again on s4c.co.uk/clic the online catch-up service.
Highlights of the games will also be shown on the channel's websites at s4c.co.uk/rygbi while the WRU will be posting regular text and video reports on the Welsh Rugby Union website.
WRU Head of Communications, John Williams, said: "Screening these games live will provide rugby fans with an excellent opportunity to stay closely involved with this vitally important tournament.
"We all know how close many of the U20 players are to senior international honours and the U20 Junior World Championships has grown in stature as a tournament year on year."