Aer Lingus is offering full refunds to customers travelling to Nice, France and Izmir, Turkey due to safety concerns.
The Department of Foreign Affairs is warning all passengers against non-essential travel to both cities.
This follows Thursday's attacks in Nice and an attempted military coup in Izmir on Friday.
Passengers due to travel to Nice and Izmir from Dublin between July 16 and 29 will be allowed to change the date of their flights for free or request a full refund.
The Department of Foreign Affairs is advising Irish citizens in both countries to exercise extreme caution and follow instructions of local authorities.