[dfawcus]

I though the point of the Irish passport card was that it is a passport (not a national ID card), but that the only place where it is needed / accepted is in other EU MS (due to format, and lack of ability to be stamped)? Note - the EU includes a passport union, which has been in place since the EEC days.

i.e. that there should be no need to also carry your passport, unless intending to travel on outwith the EU?

[messe]

You're right there isn't any need to have the passport booklet when travelling within the EU. I have the passport card on me almost 100% of the time when I'm not at home, as it's kept in my wallet. So I use that when flying within the EU as well.

However, when I'm traveling to somewhere that has a hotel safe, or somewhere secure enough to leave valuables, I'll bring the full passport booklet in my carry-on along with me, and leave it there when I go out. That way, in the unlikely event I should lose my wallet / passport card, I still have the full booklet to travel home on, rather than having to arrange emergency travel documents for the flight back.

I haven't needed it yet, but I don't see the harm in also taking it. It's not as if it takes up an obscene amount of space in my carry-on luggage, nor am I risking losing it by carrying it on my person at all times. It's purely there for peace of mind, and a backup in the very unlikely event I need it.