The man, described as white, of stocky build and around six feet tall, was caught on CCTV cameras at both garages.
Police are now appealing for witnesses after releasing the CCTV images following the burglary at Whitehall Garage in Llanon overnight on Thursday, 28 June, and an attempt to break into the Texaco Service Station at Llanarth in the early hours of Monday, 2 July.
A police spokesperson said: “Sometime overnight on Thursday, 28 June, Whitehall Garage in Llanon was broken into.
“More than £1,000 in cash was stolen, along with approximately 2,000 litres of diesel and a Volkswagen Golf with the registration number MV16 KMK.
“At around 1am on Monday, 2 July, an attempt was made to break into the front door of Texaco Service Station in Llanarth.
“The offender was disturbed on this occasion and entry wasn’t gained.”
The police added: “The man is described as white, of stocky build, six feet tall, and aged between 30 and 40.
“He was wearing a light-coloured zip-up top and tracksuit trousers, trainers, a dark baseball hat, and two-toned gloves, which were dark on the palm and light on the back of his hand.
“He was also wearing a rucksack with what appears to be a hydration tube attached to the shoulder straps.
“Anyone with information is asked to contact Dyfed-Powys Police by calling 101 and quoting reference DPP/0012/29/06/2018/01/C for the Llanon incident, or DPP/1031/02/07/2018/02/C for the Llanarth incident.”