Emergency services were called to Cullen Bay following reports of an “unidentified” item in the sea.
Police officers, lifeboat crews and coastguard teams were called at around 1pm on Sunday to search for the object, which was believed to have been reported by a member of the public in the water near Portknockie.
The coastguard’s helicopter was also assisting with the operation.
The item was described as “a dark coloured item”, but police stood down their operation around three hours later with nothing found.
Pictures from the scene showed emergency services at work on the sea and in the air.
A police spokesman said: “Officers, working with the RNLI and HM Coastguard, are currently carrying out enquiries following a report of an unidentified item seen in the sea near Portknockie.
“A dark coloured item was seen around 1pm today (Sunday) in the water at Cullen Bay near the village.
“Nothing has so far been found and no concerns have been raised about any people in the area. Inquiries are ongoing.”
They added: “Following a thorough search in the Cullen area following an unidentified object seen in the sea earlier this afternoon, emergency services are now standing down with nothing having been found.
“Thank you to everyone who assisted with our earlier appeal for information.”