A teenage girl reported she was travelling on a bus from Margate to Broadstairs when a man boarded in Northdown Road, Cliftonville, before sitting behind her and making inappropriate comments.
The victim declined to talk to the man but then felt a hand come through the gap in the seats and touch her over clothing.
The victim was able to get off the bus at Broadstairs without further issue.
The incident is believed to have taken place between 5.50pm and 6.20pm on Saturday 27 March 2021.
Officers are hoping to identify and speak to a man pictured in the CCTV images as he may be able to assist with enquiries.
Anyone with information regarding the incident should call Kent Police on 01843 222289 quoting 46/50772/21.