P&O Cruises has scrapped all sailings until 15 October owing to coronavirus, writing off the summer season.
The leading British cruise line, which is part of the Carnival group, had previously announced a pause in operations until the end of July, as the badly hit sector explored ways of operating in a post-pandemic world.
P&O said it was working with public health bodies in the UK and US to enhance health and safety protocols.
Paul Ludlow, the president of P&O Cruises, said: “As a business our operational focus is not when can we resume sailing? but how can we develop a comprehensive restart protocol that will keep everyone on board, our crew and guests, safe and well and still give our guests an amazing holiday?”
The cruise line said it would give affected customers a voucher worth 125% of their original booking, and “wanted to apologise once again to those guests waiting for refunds, particularly at a time of financial constraints”.
P&O is the first in the worldwide Carnival group to extend the operational “pause” into autumn, with most services still suspended as far as mid-July. Last month, Carnival announced hundreds of job losses in the UK.
Carnival was forced to seek $6bn (£4.8bn) in funding in March after the coronavirus pandemic halted its business. Its other UK brands include Cunard and Princess, whose ships were the first to be quarantined offshore and played a significant part in the viruss spread in Australia.
All cruise lines are searching for ways to ensure safe passage and restore public confidence. Cruises were already known for outbreaks on infections such as norovirus, and the typical clientele are of an age particularly susceptible to Covid-19.
Dozens of cruise ships are docked in Manila Bay to repatriate Filipino crew and workers who were not allowed to disembark from infected ships.