Marella Cruises has extended a pause in operations until November 15th at the earliest.
The line, the third largest in the UK, said the on-going uncertainty around travel restrictions promoted the decision.
The line had previously been expected to return to operation at the end of next month.
All customers whose bookings are impacted by the latest decision can choose from a range of flexible options.
These include amending their booking for free with a ten per cent incentive of the total value of their original booking, receive a refund credit and up to ten per cent incentive of the value of their booking or a full refund.
MSC Grandiosa returned to the seas in the Mediterranean last week, as the European cruise sector tested the water for the first time since the Covid-19 shutdown.
Marella Cruises is part of TUI Group.
There are currently five ships in the Marella Cruises fleet, Marella Dream, Marella Discovery, Marella Discovery 2, Marella Explorer and Marella Explorer 2.