The passengers and their driver escaped injury after the single-decker Arriva bus left the A442 at Danesford, near the junction with Old Worcester Road on the edge of Bridgnorth, as it approached the town from Kidderminster on route 297 at around midday on Friday.
So far no explanation has been given as to how the bus - which narrowly missed a road sign - ended up in the field.
A spokesperson for Arriva said: "We’re aware of an incident where one of our vehicles entered a field which was level with the road surface. As far as we were aware no passenger required hospital treatment although a first responder attended as a precautionary measure.
"The vehicle was recovered with minimal damage. We are investigating the cause of the accident."
The unusual sight was found by a Community First Responder. In a statement on social media on Friday, Alveley Community First Responders said: "Our team were tasked and first on scene to a service bus that left the A442 main road & entered a field at Quatford."
The volunteer medics' statement continued: "Thankfully no one was injured and all passengers were checked by a senior official West Midlands Ambulance Service paramedic officer and ourselves and assisted on to a replacement bus for their onward journey."
West Midlands Ambulance Service also confirmed that a paramedic officer attended but they were stood down as nobody was injured or required medical treatment.
West Mercia Police also attended the scene.
The bus had been removed from the field by late afternoon.
Bizarrely it was one of two buses to end up off the road and in fields in Shropshire on the same day; up near Ellesmere another vehicle went down an embankment and into a field, where it came to rest on its side, after the driver took "evasive action" to avoid an oncoming lorry on the A528 at Whitemere, near Ellesmere.
"There were no injuries," said Neal Hall, the coach company managing director of operator Lakeside Coaches. "The coach was the normal 501 bus service at 12.30pm running between Ellesmere and Shrewsbury.
"The driver had to take evasive action and the bus ended up in a field. There were 10 passengers on the bus but none received serious injuries."
Mr Hall said the driver had been shaken by the incident and added they would "see how he is" before he returns to work.
Shropshire Fire & Rescue Service, West Mercia Police and West Midlands Ambulance Service had been called to the scene.
A spokesman for the fire service said no persons had been trapped and its involvement in the incident was to make the vehicle safe.