Sections 19 and 20 of the Organisation of Working Time Act 1997, as amended by the Workplace Relations Act 2015, hold the core rules. Under section 19(1), an employee earns the greatest of three measures: 4 working weeks in a leave year with at least 1,365 hours worked, one-third of a working week for each month with at least 117 hours worked, or 8 per cent of hours worked, capped at 4 working weeks. A "working week" means the number of days the employee usually works, so the 4-week cap for a three-day-week employee is 12 days rather than 20. Certified sick days count as days worked for accrual under section 19(1A).
The employer decides when leave is taken under section 20(1), having regard to work requirements, but subject to two duties. The employer must take into account the employee's need to reconcile work and family responsibilities and the opportunities for rest available to them, and it must consult the employee, or their trade union, not later than one month before the leave is due to begin. Leave is granted within the leave year, which under section 2 starts on 1 April. With the employee's consent it can run into the six months after that year ends, and certified illness extends the window to 15 months. Holiday pay is paid in advance at the normal weekly rate under section 20(2), and section 21 deals separately with public holidays.
For a plain summary, see the WRC guidance on annual leave entitlement and accrual. Employers also carry a records duty: section 25 requires working time records, including leave, to be kept for at least three years. Our employment contracts and HR templates for Irish employers cover the written terms behind this form.