The authority has forked out to have the machines set up – one in Sheppey Gateway in Sheerness and two at Swale House in Sittingbourne.
They cost £895 each and Kent County Council joint-funded the Island’s one.
Lisa Mitchell's family have welcomed the introduction of a defibrillator at Sheppey Gateway
Between the two sites there are more than 36 volunteers trained to use them.
Former Islander Tracy Mitchell, whose daughter Lisa suffered a cardiac arrest when she lived in New Road, Minster, has welcomed the move.
Lisa and her four-year-old daughter Ellie were diagnosed with long QT syndrome, which can cause their hearts to stop unexpectedly at any time.
The family was delighted when The Dannboy Trust paid for Daisychains Nursery in Minster, where Ellie attended, to have one as it is available for anybody nearby who needs it.
Kirsty Leigh, customer services assistant, with the defibrillator at Sheppey Gateway
A defibrillator delivers an electric shock to the heart when a cardiac arrest is suffered and, according to the British Heart Foundation, with prompt defibrillation survival rates can be as high as 75%.
The machines the council have bought are fully automated, meaning they instruct the user on how to prepare the patient and attach the pads, and it will do the rest itself.
Swale’s cabinet member for community safety and health, Cllr Ken Pugh, said: “When somebody goes into cardiac arrest, every minute without CPR and defibrillation, reduces their chance of survival by 10%.
“We support the need to make defibrillators available in public places.”
Mrs Mitchell said: “This is great news – about time a local authority acknowledged the need of having a defibrillator in a public building.
“Every public building in the country has fire extinguishers, yet very few have defibrillators.
“At anytime someone can suffer a cardiac arrest, be they young or old, and the statistics for survival are so much higher if they have access to a defibrillator.
“It’s good news to hear Swale council has seen the need and is acting upon it, let’s hope other organisations follow suit.
“If the ambulance crews hadn’t had a defibrillator on board on the night of May 4, 2012, my daughter wouldn’t have survived.”