Emergency services were called to the building on Hendry Crescent at around 8.50pm on Monday after a series of fires were started in the toilets.
No-one was injured, but Police Scotland have now confirmed that they are treating the incidents as ‘wilful’.
Quick thinking staff at the community hub evacuated everyone from the building, but the toilets were left severely damaged as a result of the blaze – and that could mean an estimated £40,000 repair bill.
Liz Easton, general secretary of Kirkcaldy YMCA, said: “During our music project some of the kids said that they could smell smoke.
"Upon investigation members of staff found a small fire in the gents toilets on the ground floor.
"Staff had a chat with the kids about fire safety and then went back to their activities.
"A short time later smoke was smelled again coming from upstairs where two fires were discovered in both the men’s and women’s toilets that had been set deliberately and taken hold as staff were dealing with the first fire.
"Quick thinking staff followed fire evacuation procedures and led everyone to safety. All of the kids were calm and offering to help in anyway they could.”
Liz said both were “completely gutted” with the damage estimated at around £40,000.She added: “The lead firefighter said that the roof was two minutes away from catching on fire which would have been devastating.”
Despite the damage, the YM was open for business the following day – its grounds are being used by NHS Fife as a COVID testing centre.
"The building was open for business at 9:00am the next day – it’ll take more than a fire to shut down Kirkcaldy YMCA,” added Liz.
A Police Scotland spokesperson said: “The incident is being treated as wilful and enquiries are ongoing to establish the full circumstances.
“Anyone with information can contact Police Scotland through 101, quoting incident number 3349 of Monday, May 24.”
Two fire crews attended the scene on Monday evening.