The bollard lighting in front of the Five Islands Academy and Wellbeing Centre has been destroyed in what the Council described as a "serious act of vandalism".
All the installations are "beyond repair" following the incident, which happened last night or in the early hours of this morning.
The Council said in a statement: "We’re sorry to have to report a serious act of vandalism to the bollard lighting in front of the Five Islands Academy and Wellbeing Centre.
"During Thursday evening or early hours of Friday morning, almost all of the bollards were knocked over and the metal uprights damaged. The protective covers of the lights have also been broken off, with cables exposed and in some cases pulled out entirely, potentially putting the public at risk.
"We are currently assessing the cost of this damage, but can confirm that all of the installations are beyond repair. The wiring has been isolated and thus made safe by an electrician."
The Council’s Senior Manager for Infrastructure & Planning Craig Dryden said: “This is not the first time that the bollards have been knocked over although it is the first time that such extensive, obvious vandalism has taken place. It is one of the worst examples that I have seen whilst working on Scilly. Thankfully vandalism is rare on the islands, but incidents of antisocial behaviour like this are harmful to the reputation of Scilly and the tax payer is forced to pick up the bill.”
The Council has reported the incident and urged any residents with information to speak to the police.