If you aren’t able to travel during the month of April, then book flights to Fortaleza from Ireland during September instead. Flights to Fortaleza in September, while not as cheap as those in April, still average around 581€.
The cheapest day to depart from Ireland to Fortaleza is on a Saturday. Travellers who choose to depart for Fortaleza on a Saturday will often find tickets for as low as 566€. If your travel schedule is flexible, try to avoid departing on a Thursday because tickets tend to average around 764€. These prices are subject to change though, so be sure to set up a Price Alert for flights to Fortaleza.