iReport
If you have been the victim of racism or witnessed an incident of racism, the Irish Network Against Racism have a list of reporting centres you can reach out to at iReport Reporting Centres | INAR
You can also register the incident at the iReport, to help to monitor racism in Ireland at Irish Network Against Racism iReport
If it is a hate crime, typically, a violent crime motivated by prejudice, when a perpetrator targets a victim because of their perceived membership of a certain social group, you can report it directly to An Garda Síochána at your local Garda Station or online at Hate Crime Online Reporting - Garda
If there is an immediate risk to life/property or a crime is in progress. Or if you feel threatened in any way or are in danger, call 999 or 112.