Thirty-eight players have been named, although the squad will be reduced closer to the first game.
Coach Tamati Ellison said with eight players from the 2022 championship-winning side, and it was a good chance for players to compete for selection.
"We have a lot of guys who have been putting their hand up with their performances throughout the club season, and it's great that we can reward some of those performers in this pre-season window."
Eight of the squad have returned from Super Rugby Pacific campaigns, and their experience will be necessary for what Ellison said was a 'relatively youthful squad.'
Former All Blacks Dominic Bird and Peter Umaga-Jensen will have critical roles to play in the side's leadership.
Among the younger players named are Hugo Plummer and Dominic Ropeti and powerful Oriental Rongotai player Sione Halalilo.
"The opportunity to play first-class rugby isn't something that comes around often for most players. It's exciting for this group to see the number of potential debutants come July 12," Ellison said.
Wellington Lions Training Squad:
Forwards
Ha'amea Ahio (Johnsonville), Dominic Bird (Upper Hutt Rams), Louis Calvert (Old Boys University), Toby Crosby (Upper Hutt Rams), James Douglas (Johnsonville), Joyner Gaualofa (Tawa), Sione Halalilo (Oriental Rongotai), Akira Ieremia (Tawa), Josiah Tavita-Metcalfe (Northern United), Anthony Pettett (Johnsonville), Hugo Plummer (Tawa), Penielli Poasa (Oriental Rongotai), George Risale (Tawa), Dominic Ropeti (Oriental Rongotai), Solomona Sakalia (Northern United), Senio Sanele (Upper Hutt Rams), P J Sheck (Tawa), Nonu Tuia (Hutt Old Boys Marist), Keelan Whitman (Marist St Pats)
Backs
Zane Ainslie (Hutt Old Boys Marist), Sam Clarke (Paremata-Plimmerton), T J Clarke (Petone), Chicago Doyle (Marist St Pats), Joe Faleafaga (Paremata-Plimmerton), Losi Filipo (Petone), Kemara Hauiti-Parapara (Tawa), Logan Henry (Petone), Sam Howling (Poneke), Luke Kapene (Paremata-Plimmerton), Aidan Morgan (Marist St Pats), Louis Northcott (Paremata-Plimmerton), Ollie Paotonu (Johnsonville), Pepesana Patafilo (Tawa), Kyle Preston (Old Boys University), Isi Saumaki (Tawa), Jason Tuitama (Johnsonville), Peter Umaga-Jensen (Wainuiomata), Ethan Webster-Nonu (Paremata-Plimmerton)