Luxury line Crystal Cruises will require all passengers to be vaccinated against COVID-19 at least 14 days prior to their voyage either on its ocean and river bound ships.

The line also said it will expect all its crew to be vaccinated as well, but “this may not be a viable option for all crew members given their age and/or the availability of vaccines in their home countries.” Once vaccines are widely available, crew vaccinations will be a requirement of employment.

Crystal’s crew, who hail from dozens of countries around the world, will be expected to be vaccinated as well when the company resumes sailing, however, this may not be a viable option for all crew members given their age and/or the availability of vaccines in their home countries, the company said, in a statement.

The new measure is part of the Crystal Clean+ 4.0 measures which also include negative COVID tests for both guests and crew prior to embarkation, temperature checks at the terminal prior to boarding, mask and social distancing guidelines, enhanced cleaning and disinfection measures and reduced capacity.

Guests will now need to provide proof of vaccination before stepping aboard.

“We know that peace of mind is the greatest luxury; and the vaccine requirement is simply the best way to ensure the safest possible Crystal experience for all onboard,” Crystal’s interim CEO, Jack Anderson, said in a statement.

“As part of the company’s Crystal Clean+ 4.0 measures, crew members will be tested for COVID-19 prior to leaving their home location to join the ship and must receive a negative result. They also will take a COVID-19 test at embarkation; quarantine for seven days upon arrival; be tested again at the end of that seven-day period and must receive a negative result before beginning their duties. When vaccines are widely available, they will be a requirement of employment for crew which must be completed at least 14 days prior to service.”

In addition to providing verified documentation of their COVID-19 vaccine at the time of boarding, guests will complete an online form acknowledging this requirement before their cruise tickets will be issued.