When Irish people say southern Ireland they mean south of a line between Wexford and Limerick. I presume you mean IRELAND as in The Irish Republic or "Éire". Anyway, what you want HSBC for? Ireland has its own banks!
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RE:
Are there HSBC banks in southern Ireland?
Where are the hsbc banks in Ireland?
No there's only a corporate office here at the moment. I think I read somewhere that they would be entering retail banking in Ireland at some point in 2007-but I'm not sure.
I've just searched on HSBC branch directory and although HSBC have a branch in Dublin, it clearly states "this branch does not provide personal banking services".