For me, out of experience, Most car rental companies in Ireland allow drivers under 25, Here are some key points to take note
1)Minimum Age;21, though some companies may set it at 23. If you are under 25, you will almost always face a “young driver surcharge”, an extra daily fee that can range between €25–€40 per day depending on the rental company. This is applied because younger drivers are statistically considered higher risk.
2)Driving License; This is the key, You must have held a full, valid driver’s license for at least one or two years (depending on the rental provider). If your license is not in English, you may need an International Driving Permit (IDP).
3)Car selection;This is also limited and Drivers under 25 are typically restricted to smaller, economy cars. High-performance vehicles, luxury models, and larger SUVs are not usually available until you’re at least 25 or even 30.
4)Booking; First Booking in advance online usually gives you better rates and ensures you get a car that you’re eligible to drive. Walk-in rentals can be more expensive, and your options may be very limited.
5)Credit card deposit usually needed