Timothy Pawlett, 52, from Haverfordwest and Gareth Clement, 55, from Crymych, are alleged to have left Fishguard port early or arrived late while still claiming full working hours.
It meant they had been overpaid a combined total of over £1,800.
They both deny a single charge of fraud and the trial at Swansea Crown Court continues.
Prosecuting, Nicholas Gedge told the court Mr Pawlett was secretly logged leaving his post early or arriving late 72 times between 1 November 2015 and 17 February 2016.
Mr Clement was said to have left early on 54 occasions.
In some instances they had left two hours early.
It meant Mr Pawlett had been overpaid £1,100 and Mr Clement £710.
The alarm was raised when their boss, Det Sgt Ian Hardy could not find either of the officers before their shifts had ended.
"He was a little curious," said Mr Gedge, especially when he found both had recorded completing their full shifts.
The following night he parked outside Fishguard harbour and saw Mr Clement driving away 40 minutes early.
He drove to Mr Pawlett's home and saw his car already parked outside, which meant he must have left 30 minutes early.
Det Sgt Hardy asked for a camera with automatic vehicle number plate recognition technology to be checked and discovered "numerous" examples of them leaving early.
After their arrests neither officer disputed the data.
Mr Clement said he had been having personal and family difficulties while Mr Pawlett said he had been suffering from anxiety and depression.
Two Pembrokeshire police officers left work early 126 times in three months, a jury has heard.