More than half of payment fraud incidents reported by AIB customers this year originated from text messages.
The bank said the practice, known as smishing, accounted for 57% of the reported frauds during the first 10 months of 2025.
The figures were released as AIB urged people to be extra vigilant for scams over the festive period.
"In the run up to Christmas as people attend school plays, get through work and go to Christmas parties, while getting last minute shopping done, AIB is urging vigilance against scammers who prey on busy people becoming distracted."
With fraudsters continuing to evolve their tactics, the bank has warned that criminals are "developing sophisticated scams which are targeting individuals and businesses alike".
AIB said smishing has been the most common scam this year, based off customer data from January to October.
It involves fraudsters sending convincing texts impersonating banks, delivery services, or government agencies, urging recipients to click links, call numbers, or share codes.
The bank is advising to "never click on links or call numbers from unexpected texts".
"Always contact the sender using trusted details," it added.
It is also warning about safe account scams, whereby criminals pose as bank staff, claiming an account is compromised and instructing the account holder to transfer funds to a so-called safe account under their control.
AIB said no legitimate bank will ever ask customers to move their money for security reasons and in such cases, it has advised people to "hang up immediately".
Eight percent of the reported frauds related to investment scams, but the bank said while case volumes are lower, losses can be significantly higher.
It said scammers promise high returns through fake investment schemes, often involving cryptocurrency, bonds, or precious metals.
"If it sounds too good to be true, it probably is. Seek independent financial advice before investing."
The figures show that romance scams made up 2% of the recorded frauds.
AIB said romance scams fraudsters said to "create fake online identities to build emotional relationships and trick victims into sending money or personal information".
"Never send money or gifts to someone you haven't met in person," the bank has advised.
Money mule recruitment, whereby scammers recruit individuals to move stolen funds through their accounts, often disguised as 'easy money’ jobs, and shopping scams, which involves fraudsters setting up cloned websites or social media shops offering non-existent goods, among the other fraud incidents reported this year.
The Head of Financial Crime at AIB said fraudsters are "constantly adapting their methods, making scams harder to spot than ever before".
Mary McHale said the best defence is awareness, which she said involves "knowing what to look for and taking a moment to wait a second and double check before acting which can make all the difference".
"Ask yourself could this be a scam? You may be busy this festive season but always take the time to check."
"It could save you tens of thousands of euro and could be the difference between a merry Christmas and a broke one," she added.
Ms McHale said AIB is continuously investing to enhance its fraud monitoring systems in response to new and existing fraud trends.
She urged people to visit the security centre on the bank’s website for information on how to protect against fraud.
Last year Bank of Ireland's fraud prevention team received over 10,000 calls from customers during the peak holiday period (23 December to 29 December), with 550 calls received on Christmas day alone.
It is also urging customers to stay alert to 'smishing' scams over the festive period.
"With online shopping and parcel deliveries at peak levels, scammers are sending texts that look like they’ve been sent by trusted delivery companies, motorway toll services, utility providers, government agencies or even from the banks themselves," the bank said in a statement.
It said that those fraudulent messages often include links to fake websites designed to steal card or online banking details or trying to pressure consumers into paying a delivery or customs charge or update bank account details.
"Other 'smishing' texts will contain a fake phone number that, when called, connects you to a fraudster posing as a representative of the company or from your own bank."
Bank of Ireland also said that its dedicated fraud support team is available 24 hours a day, seven days a week throughout Christmas and into the New Year.
