It comes after the line reinstated mask wearing on Island Princess last week following a number of positive Covid tests amongst staff and guests.
The company has since reintroduced face coverings on Alaska cruises onboard Royal Princess, Majestic Princess and Grand Princess sailing from Whittier and Vancouver until further notice. Guests will be provided with a mask if needed.
A spokesperson for the line said: "In an abundance of caution masks are required in indoor locations on Alaska cruises aboard Royal Princess, Majestic Princess and Grand Princess sailing from Whittier and Vancouver until further notice. Masks will be provided to guests if needed."
