Disney Cruise Line will require passengers 5 and older to be fully vaccinated against covid-19 as of Jan. 13, the operator said Wednesday.

The cruise line, which operates four ships, became the first to update its vaccine policy with a mandate for young kids since they became eligible for the coronavirus vaccine this month. The White House said Wednesday that an estimated 2.6 million children in that age group have gotten their first shot.

Some companies including Norwegian Cruise Line have prohibited all unvaccinated people — including children who were not yet eligible — from sailing. But most lines have required passengers 12 and older to be vaccinated, with extra testing requirements for younger kids.

Before the requirement goes into effect in January, Disney said kids ages 5 to 11 who are not vaccinated must have proof of a negative coronavirus test taken between three days and 24 hours before they board a ship. The testing requirement applies to younger kids as well.

“We are resuming sailing in a gradual, phased approach that emphasizes multiple layers of health and safety measures, considering guidance from the U.S. Centers for Disease Control and Prevention and other medical experts. Under this guidance, we’ve reimagined your cruise experience so we all can enjoy the magic responsibly,” the company said on its website.

Larger cruise lines — which also cater to families with kids — have added some language about younger kids without putting mandates into place.

Royal Caribbean International says kids between 5 and 11 who have been vaccinated can show proof and follow the less-strict protocols for vaccinated passengers.

Carnival Cruise Line requires everyone to be vaccinated, but it grants “a very small number” of exceptions for those with medical exemptions and kids under 12. The cruise line says on its website that exemptions for kids are not guaranteed.

“Given our experience with sailings in previous months, we know we cannot honor most requests for exemptions,” Carnival said in a statement. “So now that U.S. health officials have approved the covid-19 Pfizer vaccine for children ages 5-11, getting children into the fully vaccinated category will allow more of them on board, and allow them access to the guest experience our current guests are enjoying.”

Youth programs, once open, will be available to fully vaccinated children and teens. Carnival said it will require vaccinations at least through March 2022.

“While the decision to vaccinate children is obviously a personal one, if you are a family with children ages 5-11 and want to guarantee your ability to sail together, we encourage you to consider your vaccination options,” the Carnival website says.