The team will be captained by the returning Dragons RFC back row Ryan Woodman who missed the Six Nations championship through injury and includes just two uncapped players, brothers Ioan and Steffan Emanuel.
Wales will face New Zealand, Spain and France in the U20 Championship pool stage, kicking off on 29 June.
“Yesterday was a tough day, telling players who have worked incredibly hard that they haven’t made the plane,” said Whiffin.
“There were obviously some tough conversations but to be fair they’ve reacted well and the group have got tight around them and picked them up. But that is the nature of the job.”
Hooker Isaac Young, along with the Emanuel siblings and Woodman, are the only players in the squad who didn’t feature in the Six Nations championship. Young played for Wales last year but was ruled out for this year’s campaign through injury.
“We have got power throughout the team with genuine athletes in all areas of the field,” said Whiffin,
“The way we want to play is to move the ball and express ourselves in the wider channels – hopefully we have a team who can be competitive in what is an extremely competitive pool.”
Whiffin welcomed the return of the influential Woodman whose absence was a huge loss during the Six Nations.
“He has had a massive impact in the two weeks he has been in with us,” explained Whiffin.
“He has come back in, in very good nick after his injury-forced absence. His physicality now will be a key addition to the squad but not only that, his calmness around the group is also a positive effect. He is a natural leader and the players look up to him.”
Wales U20 Championship squad
Forwards
Jordan Morris (Dragons)
Josh Morse (Scarlets)
Ioan Emanuel (Bath Rugby)
Harry Thomas (Scarlets)
Isaac Young (Scarlets)
Will Austin (Sale Sharks)
Kian Hire (Ospreys)
Sam Scott (Bristol)
Jonny Green (Harlequins)
Nick Thomas (Dragons RFC)
Osian Thomas (Leicester Tigers)
Ryan Woodman (Dragons RFC – Capt)
Lucas de la Rua (Cardiff Rugby)
Harry Beddall (Leicester Tigers)
Morgan Morse (Ospreys)
Owen Conquer (Dragons RFC)
Backs
Ieuan Davies (Bath Rugby)
Rhodri Lewis (Opsreys)
Lucca Setaro (Scarlets)
Harri Wilde (Cardiff Rugby)
Harri Ford (Dragons RFC)
Macs Page (Scarlets)
Steffan Emanuel (Cardiff Rugby)
Louie Hennessey (Bath Rugby)
Elijah Evans (Cardiff Rugby)
Aidan Boshoff (Bristol Rugby)
Harry Rees-Weldon (Dragons RFC)
Kodie Stone (Cardiff RFC)
Huw Anderson (Dragons RFC)
Matty Young (Cardiff Rugby)
Wales U20 pool fixtures
Saturday 29 June, Wales v New Zealand, Athlone Sports Stadium, 6pm
Thursday 4 July, Wales v Spain, Athlone Sports Stadium, 1pm
Tuesday 9 July, Wales v France, Athlone Sports Stadium, 3.30pm
Listen to Richard Whiffin interview here
