The Tigers pair have been included in Tongan head coach Toutai Kefu's 31-man squad and will take on Argentina, France and the USA, as well as coming up against their Leicester club mates when they play England in the Group C opener on Sunday, September 22.
The Tongan duo will line-up against their Tigers team-mates George Ford, Dan Cole, Ellis Genge, Manu Tuilagi, Ben Youngs and Jonny May in their opening fixture of the 2019 tournament before a possible encounter with incoming Leicester lock Tomas Lavanini in their fixture against Argentina on Saturday, September 28 in Osaka.
The Pacific Isles nation will then meet France (October 6) and the USA (October 13) in their final pool matches.
Veainu will be competing in his second World Cup while his Tigers team-mate Kalamafoni will make his third successive appearance at the tournament after featuring in 2011 and 2015 for his home-nation.
Former Tigers Steve Mafi and Afa Pakalani have also been included alongside the current Leicester squad members.