https://www.citizensinformation.ie/en/health/health_system/health_services_and_visitors_to_ireland.html#l0b797
If you are here for a shorter period, you are regarded as a visitor and you do not have any entitlement to free or subsidised health services. You may wish to consider taking out travel insurance.
People who are not entitled to free health services
If you are not ordinarily resident and you are not entitled to health care under any of the circumstances described above, the HSE may apply the full economic cost for any services provided. In cases of hardship the HSE may provide urgent necessary treatment at a reduced charge or without charge.