'Dolphin' was a British maritime intelligence-gathering undertaking in preparation for 'Cordite' (March/April 1941).

Allocated by General Sir Archibald Wavell, the commander-in-chief, Middle East, to Lieutenant Colonel Dudley W. Clarke, heading the theatre’s deception apparatus, the operation was created to generate intelligence information about Rhodes, and was undertaken by a small ketch, which sailed through the Dodecanese islands group for the purpose.