A number of post boxes were painted between Wednesday, January 31 and Monday, February 5, 2024, with the majority of the incidents in the Temple Hill area.
They have been noticed on several streets, including Keynes Road, St Vincents Road, Victoria Road, Pilgrims Way, Fulwich Road, and Welcome Avenue.
A particular one on Farnol Road is different to the others, sporting a black and white pattern that looks a little like a cow print.
Royal Mail says it is in the process of restoring the post boxes to their original red painting.
Police have released an image of a person they would like to speak to in connection with the incidents of criminal damage.
Inspector Siobhan Rowe, of the Dartford Community Safety Unit, said: “Our officers have been working closely with the Royal Mail after several post boxes were covered in paint.
“We are now issuing an image of a person who may be able to assist with our enquiries.
“While their face is concealed, they are wearing distinctive clothing and we are hoping somebody recognises them and contacts us.”
Drivers with dashcam and residents with private CCTV are being asked to check for footage that may assist the investigation.
Anyone with information is urged to call Kent Police on 01474 366149, quoting reference 46/19948/24.
You can also call Crimestoppers anonymously on 0800 555111 or complete the online form on their website.