You generally need your landlord’s written consent before sub-letting or assigning an Irish tenancy; do not assume that finding a replacement tenant is enough. If sub-letting is agreed, you usually remain responsible to the landlord for the rent, the property and breaches of the tenancy, even though the sub-tenant pays you. Your landlord may refuse or impose reasonable conditions, and you should record any agreement in writing, including the rent, deposit and duration. Unauthorised sub-letting can lead to enforcement action or termination issues, which the RTB would assess based on the tenancy’s facts.