Knife Law Ireland
Knife law in Ireland generally falls into two categories, outright prohibition and allowed but with caveats, remember just because a knife might not be prohibited outright does not mean you can legally carry in public, you CANNOT carry any type of knife in public no matter what size the blade, folding or fixed. without a valid reason, the validity of said reason is in of its self not a black and white area, it will usually fall on the guard in question to use his best judgement as to the validity of the reason proffered.
If your knife is being carried while hunting or fishing or as part of your trade such is likely to be construed as a valid reason although my own recommendation is that to and from the hunting, fishing and trade areas keep your knife in the boot of your car in your tool or tackle box where it is not readily accessible.
The same knives in a different context such as forgetting you have your knife in your back pocket while having a few pints in the local or queuing for a kebab will be viewed as a crime by any guard with the final word going to the judge, convictions under ‘section III of the offensive weapons act’ can carry a fine of up to €1000 and 1-5 years in prison.
A list of prohibited knives in Ireland includes, Offensive weapons include flick-knives, knuckledusters, swordsticks, sword umbrellas, hand and foot claws, belt buckle knives, pushdaggers, hollow kubotans, shurikens, butterfly knives, telescopic truncheons, blowpipes, kusari gama, kyoketsu shoge, manrikigusari, sap gloves, and machetes.
See http://www.justice.ie/en/JELR/Pages/FAQ for more information.