Carnival Corp plans to pull up anchor on seven more ships, but voyages will cost a little more for unvaccinated passengers on its Carnival Cruise Line brand.

The cruise behemoth will almost double its active fleet to 15 ships by October, but guests who have not been inoculated against Covid-19 will get hit with a $150 surcharge.

Brand president Christine Duffy said that the fee would be added to cover the costs of testing, reporting and health and safety screenings needed for unvaccinated passengers.

"Carnival will continue to welcome unvaccinated guests on board, but all unvaccinated guests including children under the age of 12, will be subject to pre-cruise and pre-embarkation testing and testing again prior to debarkation on cruises longer than four days," she said.

Unvaccinated guests sailing from Florida effective 31 July and Texas effective 2 August will also need to show proof of travel insurance coverage, based on itineraries and port requirements.

Carnival Cruise Line, with 22 ships and one vessel on order, is also limiting participation in its supervised youth programs to vaccinated children and youth 12 years and older.

"These additional measures will be in place through at least October but may be extended based on guidance from public health and medical advisors and the requirements of destination partners," Duffy said.

Exemptions will apply

Duffy said Carnival Cruise Line will waive the $150 surcharge for a limited number of unvaccinated guests who plan to sail within 14 days as it finalises the vaccinated guest count.

"The more bookings we initially secure for our cruises with fully vaccinated guests, the more exemptions we can ultimately offer for those unvaccinated guests already booked and those wishing to sail," she said.

Calls asking Carnival if it was holding voyages at full capacity were not immediately returned.

Miami-based competitor Royal Caribbean Group is carrying out cruises at 40% capacity.

Carnival Cruise Line expects to resume revenue sailings on the 2,980-berth Carnival Glory (built 2003) from New Orleans on 5 September and the 2,124-berth Carnival Pride (built 2001) from Baltimore on 12 September.

If all goes well, Arnold Donald-led Carnival, which owns 91 ships across nine brands, will then launch the 3,646-berth Carnival Dream (built 2009) from Galveston on 19 September.

The New York-listed cruise line also expects to sail the 2,980-berth Carnival Conquest (built 2002) on 8 October and the 2,980-berth Carnival Freedom (built 2006) on 9 October, both from the Port of Miami.

It intends to resume guest sailing on the 2,190-berth Carnival Elation (built 1998) from Port Canaveral on 11 October and the 2,634-berth Carnival Sensation (built 1993) from Mobile on 21 October.

It had postponed planned trips on Carnival Pride from Baltimore, Carnival Dream and Carnival Sensation.

Itineraries on the 2,124-berth Carnival Miracle (built 2003) from Long Beach have been pushed back to 24 September.

Voyages on the 3,006-berth Carnival Sunshine (built 1995) from Charleston, the 2,606-berth Carnival Ecstasy (built 1991) from Jacksonville and the 2,974-berth Carnival Liberty (built 2003) from Port Canaveral have been cancelled through 31 October.

Carnival announced in late June that it plans to have 56 ships holding revenue sailings by the end of the year.