Almost half of the incidents occurred in Dublin and more than two in five of the victims were aged under 25.
Gardaí are warning students to be wary of "rental scams" after revealing that €900,000 was stolen from people affected by the scams between 2019 and 2021.
Gardaí are advising people to be cautious of the scams, particularly at this time of year when students are returning to college.
While incidences of accommodation fraud have declined in recent months due to Covid-19 restrictions, Gardaí have highlighted that the new generation of third-level students seeking accommodation could be a target for fraudsters.
There were a total of 503 cases of rental scams reported between 1 February 2019 and 31 May 2021, with incidents declining in the last 18 months, likely due to Covid-19 restrictions, which meant a majority of college students were studying from home over the last academic year.
Just over €900,000 was stolen in rental scams over this period, with almost half of these incidents occurring in Dublin.
42% of all injured parties were under the age of 25, while 72% of all injured parties were under the age of 35.
Detective Superintendent Michael Cryan of the Gardaí National Economic Crime Bureau urged people on Tuesday to "only use recognised letting agencies or deal with people who are bona fida and trusted".
"Websites can be cloned, check the URL to ensure it’s a real website and take note of the privacy and refund policy sections," he said.
"Be very wary of social media advertisements or where a person letting the location will only communicate via messenger or WhatsApp. You should push for direct answers and if responses are vague disengage immediately."
Cryan also encouraged people to never transfer money, pay cash, or pay in cryptocurrency, to avoid getting scammed.
"Watch out for unsolicited contacts or where the contact appears to be based in other jurisdictions and especially if there is a sense of urgency like 'a one-time offer'," he added.
"If you have decided to take up the offer, only use trusted money transfer systems, I would recommend using a credit card.
"Be wary if a website is asking you to send money to a random PayPal address, wire it by Western Union, pay in iTunes gift cards or only deals in cryptocurrency. The majority of the time, those methods are done to avoid scrutiny and ensure that a transaction can’t be reversed."
