Vearncombe, an S14 swimmer, won four British finals in Aberdeen in February and produced times that would have put him at the top end of the fields in the World Series event running alongside the national meet.
He will now get the chance to take on the world’s best in June and make his GB debut, alongside his club colleague Dunn.
Dunn, also an S14 swimmer, is one of seven Tokyo Paralympic champions in a 30-strong British team. The Plymouth Leander star was Team GB’s top performer at the Paralympics in Tokyo last year, winning three gold medals, one silver and one bronze.
“Tokyo was a huge success under challenging circumstances last year, however we’re now focussed on positively building momentum into this new Paralympic cycle and it’s exciting to welcome some new faces to the team.
“We’ll continue working closely with these athletes and their home programmes on progression plans to enable them to arrive at the Championships in a position to deliver their best possible performance.”
British Swimming associate performance director Tim Jones added: “With a shortened cycle into the next Paralympic Games, these World Championships in June are one of the foundation stones as we build towards our Paris 2024 objectives.
“The team selected bonds together a terrific blend of experienced names and exciting prospects – this combination will not just make us competitive on the medal front, but presents a key development opportunity for our next generation to refine their craft in the international arena.”
The World Para Swimming Championships will take place between June 12 and June 18.