I’ve been looking into Ireland for undergrad studies and came across IELTS stuff everywhere. Do you have to give IELTS to study there? Can someone explain it in simple terms please? 
Yeah I had the same doubt a few weeks back 
Basically, most Irish universities do ask for IELTS or some kind of English proficiency test. It’s their way of checking if you’ll be able to manage the courses.
It depends on where you’re applying from and what your medium of instruction was. Like, if your previous schooling was all in English, some unis might waive it off — but not all. So you’ve to check with each uni individually.
Also heard that if you’ve done English in 12th and scored decent marks, a few colleges might give you an exemption. But it’s not a guarantee. That’s where the whole “why IELTS is necessary” thing comes in. Safer to take it tbh.