Shares of the Miami company were off 2.7% to $15.26.
Carnival also canceled five cruises scheduled to operate from Sydney from Jan. 16 through Feb. 8.
"Following the U.S. Centers for Disease Control's decision to extend its no-sail order for cruise operations until Oct. 31, Carnival canceled all but PortMiami and Port Canaveral cruises for the rest of the year," Carnival said in a statement. "It has now determined that November 2020 operations will not be feasible."
The cruise industry has been battered by the coronavirus pandemic, with outbreaks and deaths occurring on several vessels.
Carnival said it was working on protocols and procedures that would enable cruises to resume with a phased-in approach, designating Miami and Port Canaveral as the first two home ports for embarkations.
"Cruises currently scheduled for December from those two home ports remain in place for the time being while Carnival evaluates options," the company said.
Last week, Carnival posted a third-quarter net loss of $2.86 billion, compared with a profit of $1.78 billion a year earlier.
The CDC's no-sail order has been the source of some controversy, after the agency's director Robert Redfield, was reportedly overruled when he pushed to extend the order on passenger cruises into next year.