Workers from the Bog Visitor Centre say they have been shocked by the incident, which they say is the first of its kind in the area.
On Sunday, cars left in the car park next to the visitor centre at the Stiperstones had their windows smashed and thieves took handbags containing mobile phones and other valuables.
The thefts, which took place between 12.30pm and 1pm, have shocked those who work at the visitor centre, who say it is the first time they have had a crime like this in broad daylight.
Chairman and coordinator Noel Evans had been working in the visitor centre in the afternoon and said the centre had been particularly busy with visitors at the time the thefts took place.
He said: "It was two couples in two cars. One of the couples came back into the visitor centre to use the phone and report it to the police.
"It is the first time it has ever happened up there. It was a bit of a shock because it was in broad daylight on a busy day."
Police have urged people to be careful leaving valuables on display in their cars when they are left unattended.
Anyone with information about the thefts is urged to call West Mercia Police on 101, quoting incident 0392S of August 28.