Passengerships will start sailings in and out of Florida ports by tomorrow as Irma rolls away from major shipping lanes.
The lines also plan to deliver supplies to many of the Caribbean islands that have been battered by Irma.
The storm, one of the largest to hit the US, was downgraded to a tropical storm and is expected to exit the Florida coast by late Monday.
With the storm now making its way out of the region, Carnival says it plans to have three cruise itineraries depart Miami by tomorrow, the company said. Another ship will depart Miami by Wednesday.
Carnival says it will also resume voyages from ports further north of Miami, including Port Everglades and Port Canaveral. Another Carnival ship departed Puerto Rico on the weekend.
All in, the Arnold Donald-led company cancelled three cruises while Irma rattled through the Caribbean last week.
Royal Caribbean said three cruise itineraries will start up tomorrow and one on Wednesday.
With the itinerary impacts not as bad as feared, shares in both New York-listed companies leapt on Monday with Carnival rising almost 1% and Royal Caribbean shares up 2%.
Cruise ships join humanitarian efforts
Royal Caribbean said its 3,114-berth Adventure of the Seas (built 2001) made a humanitarian stop in St Maarten on Sunday. Most of the island's buildings were destroyed by Irma.
The 2,356-berth Majesty of the Seas (built 1992) will call on St Thomas and St Maarten to provide supplies and transport evacuees. The 1,602-berth Empress of the Seas (built 1990) will assist the Florida Keys with any emergency supply needs.
Carnival says it plans to also bring relief supplies and is coordinating with local officials on what is needed.
