(10 a.m. GMT) -- P&O Cruises has cancelled all its planned cruises until the beginning of September and those on Britannia and flagship Iona -- which has not even sailed with passengers yet -- until the beginning of October.
The line will instead offer a series of short break and week-long UK cruises, which will go on sale later in March.
Just last week, the line stopped selling its summer cruises, prompting people to speculate that a full cancellation was imminent.
P&O Cruises president Paul Ludlow said: "Following recent Government announcements and as the vaccine programme is rolled out across the globe we can all begin to feel a sense of reassurance and hope that this current lockdown period in the UK will come to an end.
“Whilst holidays here in the UK will be the first to become a reality we will, of course, gradually see the return of international travel but first we want guests to be able to enjoy a proper summer holiday at sea with the best in relaxation, entertainment and dining choice.
“These sailings will leave from our home port in Southampton and sail around UK coastal waters enjoying the summer sunshine. More details of dates, prices and the experience on board will be announced later this month."
He added: "In order to offer these UK breaks it does mean that unfortunately we need to cancel some of our current published programme of holidays this summer. Cruises on Arcadia, Aurora, Azura and Ventura have been cancelled until the end of August and on Britannia and Iona until the end of September."
However he did say that the line was in close contact with the UK government and the task force set up to report back on April 12 about international travel restrictions being lifted.
"From the moment we see travel restrictions lifting we will begin the significant logistical task to re-start our operations. It will take some time for the first ship to return to service, followed by the phased return of the remaining fleet," Ludlow added.
"We cannot wait to welcome everyone back on board with the protection of effective protocols to safeguard the health and wellbeing of all crew and guests."
Most of the fleet is moored off the south coast of England, where it has been since worldwide cruising paused on March 13, 2020.