Under the line’s Crystal Clean+ health and hygiene protocols, travellers must be fully inoculated with a Covid vaccine at least 14 days prior to their embarkation date. 

Guests must provide documented proof of vaccination at the time of check-in before boarding the ship.

Crystal said extending its vaccination rule would allow guests freedom to explore onshore and “hassle-free travel across multi-country itineraries”. 

Senior vice-president and managing director Walter Littlejohn added: “The health and safety of our guests and crew is paramount to everything we do at Crystal River Cruises and, as such, we will require full vaccination through 2022 so that our guests can continue to explore the world in great comfort and safety.

“After months of planning and preparation we welcomed guests back onboard in late August and the feedback has been wonderful. Extending the vaccination requirement provides our guests with the health and safety information and assurances they need to plan future travels.”