The line has delayed its plans to reposition Discovery to the Mediterranean owing to the ongoing conflict in the Middle East.
Discovery was one of six ships left stranded in the Gulf region when the US and Israel launched strikes on Iran late last month.
Others included MSC Euribia, also in Dubai, and Celestyal Journey, which has been confined to port in Doha.
All guests have now disembarked both Celestyal Discovery and Celestyal Journey, with Celestyal stressing both ships are fully operational.
However, the line has confirmed it has had to delay Celestyal Discovery's repositioning ahead of the start of its Mediterranean programme.
Celestyal has cancelled Discovery's three-night Iconic Greek Islands sailing departing 27 March and four-night Iconic Greek Islands sailing departing 30 March.
The line said the move came as it "finalises arrangements for the ship’s repositioning to the Mediterranean ahead of the summer season".
It added the two ships' departure from the region would take place "in line with guidance from the relevant authorities".
Guests booked on either of these voyages will be able to opt for a full refund or future cruise credit.
"We continue to monitor developments closely and remain focused on resuming our planned programme as soon as possible," said Celestyal. "We thank our guests and valued partners for their patience and understanding."