The former couple, whose relationship was recently rocked by the actress' cheating scandal, have reportedly decided to skip the event to avoid questions on their personal lives, reported Aceshowbiz.
Actor Taylor Lautner, who plays Jacob in the Vampire series, will not attend the events as well.
"The passion and dedication of Twilight fandom has been amazing and we're out to throw one last giant convention, a final gathering to see old friends that have made up the Twilight family."
"Although Rob, Kristen and Taylor will not be with us this time out we will have a super line-up of other Twilight stars and the weekend will be filled with special events, movie prop and costume displays, contests, panels, auctions, parties, exclusive merchandise, music and much more, including some surprises!," Creation Entertainment said in a statement.
The conventions are scheduled to take place on the weekends leading to the release of "The Twilight Saga's Breaking Dawn Part II".