The majority of cruise lines will require travelers to be fully vaccinated (having received all required doses) at least two weeks prior to departure.
For children, this requirement will apply to teens 16 and older from July 1st and childs 12 and older from August 1, 2021.
Norwegian Cruise Line will require travelers to submit proof of vaccination for all travel by October 31, regardless of age. This includes children. NCL offers reimbursement to people who could not comply with this rule.
Royal Caribbean and Celebrity will also require passengers to be vaccinated, but only for those 12 years of age and older. The children will have a Covid-19 test before departure. All passengers may be required to undergo a Covid test if required by local authorities.
Other companies will require a negative Covid test before departure. These include Holland America and Azamara, Le Ponant and Viking.
Seabourn will require the vaccination of all passengers including children.