Head coach for the tour, Robin McBryde, has selected a squad that includes 15 players who formed part of the successful 2013 RBS 6 Nations squad and features 11 uncapped players.
Wales face Japan in Osaka on Saturday, 8 June in the first Test before travelling to Tokyo for the second fixture a week later on Saturday, 15 June.
The training squad will be reduced ahead of the tour with 27 players travelling to Japan.
In the front-row Ryan Bevington (Ospreys), Ken Owens (Scarlets), Scott Andrews (Blues) and Craig Mitchell (Exeter Chiefs) who all featured during the RBS 6 Nations, are joined by Rhys Gill (Saracens), Sam Hobbs (Blues), Scott Baldwin (Ospreys) and Scarlets duo Emyr Phillips and Rhodri Jones.
Bradley Davies (Blues) returns from injury to be named in the squad and is joined by his Blues team-mate Lou Reed.
Andrew Coombs (Dragons) who made his debut against Ireland in February, is included along with James King (Ospreys).
Aaron Shingler and Rob McCusker (both Scarlets) feature along with uncapped trio Josh Navidi, Andries Pretorius (both Blues) and Ospreys’ Dan Baker.
Lloyd Williams (Blues), Tavis Knoyle and Aled Davies (both Scarlets) are named as the scrum-halves alongside fly-halves Rhys Priestland (Scarlets) and Dan Biggar (Ospreys).
The backline also features Ospreys trio Ashley Beck, Jonathan Spratt and Dafydd Howells alongside Harry Robinson and Owen Williams (both Blues), Scarlets duo Scott Williams and Liam Williams and Tom Prydie (Dragons) and Steven Shingler (London Irish).
“We have selected a squad with the right blend of experience and youth and this is a great opportunity for players to make their mark on the international stage,” said McBryde.
“It’s a chance for some players to experience the international environment for the first time but it’s also an opportunity for players who have been involved previously to take the next step as we look to develop leaders.
“We are travelling to Japan as RBS 6 Nations Champions and are focused on the two-Tests that await us there and we will be looking to finish the season on a high.”
Wales Training Squad:
Forwards: Ryan Bevington (Ospreys), Rhys Gill (Saracens), Sam Hobbs (Blues), Ken Owens (Scarlets), Emyr Phillips (Scarlets), Scott Baldwin (Ospreys), Scott Andrews (Blues), Craig Mitchell (Exeter Chiefs), Rhodri Jones (Scarlets), Bradley Davies (Blues), Lou Reed (Blues), Andrew Coombs (Dragons), James King (Ospreys), Aaron Shingler (Scarlets), Dan Baker (Ospreys), Rob McCusker (Scarlets), Andries Pretorius (Blues), Josh Navidi (Blues).
Backs: Lloyd Williams (Blues), Tavis Knoyle (Scarlets), Aled Davis (Scarlets), Rhys Priestland (Scarlets), Dan Biggar (Ospreys), Scott Williams (Scarlets), Ashley Beck (Ospreys), Owen Williams (Blues), Jonathan Spratt (Ospreys), Dafydd Howells (Ospreys), Liam Williams (Scarlets), Harry Robinson (Blues), Tom Prydie (Dragons), Steven Shingler (London Irish).
