The Court of Justice of the European Union (CJEU) has ruled that calls to an after-sale service line must not cost more than the cost of a standard call to a landline or mobile number.

See https://www.out-law.com/en/articles/2017/march/cost-of-after-sales-call-must-not...

This clearly precludes the use of numbers starting 1850, 1890, 0818 or 076.

ComReg is changing the rules on call charges for certain non-geographic numbers from 1 December 2019.

Numbers starting 1850, 1890, 0818 and 076 will change to be inclusive in allowances on landlines and on mobiles on the same basis as calls to Irish landline numbers, or otherwise charged at the same rate as calling an Irish landline number. This will make them somewhat equivalent to how 03 numbers work in the UK.

A few years after that change, the 1850, 1890 and 076 number ranges will be withdrawn from use on 1 December 2022, leaving just the 0818 number range for this purpose. All users of 1850, 1890 and 076 numbers who wish to continue using a non-geographic number will need to migrate to a brand new number in the 0818 range before that date.

Separately, the 1800 number range will remain as the single freephone number range.

Premium rate numbers are unaffected by these changes. These are the numbers starting 15xx, where xx gives a clue as to the likely call charge.

Backtracking to 2018, there's an interesting and useful analysis of the 2014 consumer protection changes as they were applied in Ireland, here:

https://deryck.blog/2018/02/08/sky-high-call-charges-0818-basicrate-directives/