Cruise ships docked in St. Thomas on a hazy day

(11:40 a.m. EDT) -- As if all the new ships launching in spring 2018 aren't exciting enough, Carnival Cruise Line and Norwegian Cruise Line have revealed the itineraries their respective new 2019 ships will sail when they debut next year. Both also opened bookings for the cruises.

Carnival Cruise Line

Carnival Panorama will sail seven-night, three-port Mexican Riviera cruises when it debuts in December 2019. The ship -- the third in the line's Vista-class -- will be the first new Carnival ship to homeport on the west coast in 20 years.

The weeklong sailings will depart every Saturday, beginning on December 14, from Long Beach, California. Port stops include Cabo San Lucas, Mazatlan and Puerto Vallarta.

Prior to the launch of the weekly seven-night service, Carnival Panorama will offer a one-time-only three-night cruise to Ensenada, departing from Long Beach on December 11.

Carnival Panorama is under construction at the Fincantieri shipyard in Marghera, Italy. Like the line's other Vista-class ships, it will feature the SkyRide, a large WaterWorks aqua park, and Havana Cabana and Family Harbor accommodations.

Cruise ships docked in St. Thomas on a hazy day

Norwegian Cruise Line

On the other side of the U.S., Norwegian Encore, the line's fourth and final Breakaway-Plus-class ship, will sail to the Eastern Caribbean during its inaugural 2019 season. (Norwegian's Breakaway-Plus class includes Miami-based Norwegian Escape, China-based Norwegian Joy and Norwegian Bliss -- the line's newest ship, purpose-built for Alaska cruises and scheduled to launch in April 2018.)

Sailing out of Miami every Sunday from November 17, 2019 to April 12, 2020, Encore will sail seven-night itineraries that visit San Juan, Puerto Rico; St. Thomas, U.S. Virgin Islands; and Tortola, British Virgin Islands.

Norwegian has yet to release any details about Encore; the 4,000-passenger ship is under construction at the Meyer Werft shipyard in Papenburg, Germany. It will sail from Norwegian's new cruise terminal in PortMiami.

--By Dori Saltzman, Senior Editor