Constructed by Cammell Laird Shipyard of Birkenhead, United Kingdom, she entered service in 1940 during World War II.

[2][page needed] Dido then spent four months on convoy duty in the Atlantic before running supplies to Malta where she joined the Eastern Mediterranean Fleet in April 1941.

From July to November 1941, Dido was sent to the Brooklyn Navy Yard in New York City for a refit, rejoining the Eastern Mediterranean Fleet in December 1941.

The first three months of 1942 were spent on convoy escort duty between Alexandria and Malta but in March that year, Dido took part in a bombardment of Rhodes.

A week later Dido joined the cruisers Cleopatra, Penelope, Carlisle, and Euryalus under the command of Rear Admiral Philip Vian at the Second Battle of Sirte.

The only working dry dock in Massawa was not large enough to lift Dido entirely so she was partially floated up to clear the stern, leaving the bow low in the water.

[4] Dido then spent the rest of the year supporting the British campaign in North Africa before being transferred to the Western Mediterranean Fleet in December 1942.

On return to service, Dido spent time in Malta and Taranto before taking part in a diversionary action off Civitavecchia in support of the Anzio landings.