Police are appealing for witnesses after a series of attacks on buses.
Go Coach cancelled its 429 service after youths attacked it with a pole and an air rifle, near the Gamecock pub in London Road last Thursday.
Police confirmed two further incidents this Monday at 4.55pm in Fawkham Road and at 5.45pm in Hever Road.
On these occasions objects were believed to have been fired from catapults causing damage to the buses.
A pupil was struck by the glass but was unharmed.
Patrols in the area have now been increased and investigations to identify those responsible, including reviewing CCTV, is ongoing.
Inspector Mark Stubberfield, of the Sevenoaks Community Safety Unit, wanted to reassure the public they were working to catch the perpetrator.
"It is only through luck that these reckless acts haven’t resulted in someone being seriously injured or worse," he said.
"On top of that, the damage has caused significant financial loss to the bus company and these actions will result in changes to bus routes as well as withdrawal of services.
"I want to reassure the public that we will use the full extent of our powers to ensure any offenders are held to account for their irresponsible and dangerous conduct and brought to justice."
The company affected, which is based in Sevenoaks, say more than £1,500 of damage has been done to its vehicles, including a large hole in the windscreen.
Managing director Austin Blackburn said: "The driver said he saw around eight youths attack the coach.
"It's not good at all. We've had to stop sending our buses into West Kingsdown until there's some confirmation that our passengers or staff won't be hurt."
The bus company explained it is still running the S11 to South Darenth and 413 to Meopham as it "should be safer due to earlier times".