Thieves broke into a study centre at a wildlife reserve and stole cash from a safe.
The burglars climbed in to the building at Monkton Nature Reserve through a window, before grabbing the money and fleeing.
Police are now appealing for witnesses and want to speak to anyone who saw any suspicious behaviour.
The incident took place between 3pm on Monday, February 20 and 9am on Tuesday, February 21.
Officers also want to speak to anyone who saw a white Vauxhall Vivaro van in the area on the afternoon of Sunday, February 19.
Anyone with information should call police on 01843 222289 or Kent Crimestoppers anonymously on 0800 555111 quoting reference number ZY/6924/17.