It is understood one of the victims was convinced to transfer large amounts of cash, having met with fraudsters via an online dating site.
The arrests in West Dublin and Navan in Co Meath follow complaints of suspected romance and investment fraud.
Officers believe one of the victims in the case was convinced to transfer large sums of cash to accounts in Ireland, Turkey, Dubai and Vietnam over a nine month period.
Gardaí made three arrests today during search operations, and a number of devices were seized.
They say they expect numerous injured parties from all over the world will now be identified, and they are encouraging victims of this type of fraud to report incidents to local Gardaí.
The men arrested today can be held for up to seven days.