Brussels, 20 August (Brussles Morning Newspaper)Â Belgian workers who fall ill during annual leave have the right to reclaim those holiday days, yet evidence suggests the entitlement remains surprisingly underused. More than two years after the rules changed, many employees are still failing to recover sick holiday days that could be taken at another time.
Holiday days no longer have to be lost to illness
The change came into force on 1 January 2024 and addressed a straightforward problem: an employee could book a week away, become ill and effectively spend part of their annual holiday on sick leave.
Under the current rules, statutory annual leave that coincides with a period of incapacity for work can be preserved and taken later.
The protection applies when the employee follows the required procedure, including promptly informing their employer and providing medical evidence.
Yet early evidence showed relatively few workers were actually making use of the change.
An Acerta analysis of more than 467,000 employees found that by late October 2024 just 0.0265% had converted statutory holiday into sickness days. That amounted to roughly one worker in every 3,772.
Illness on holiday is far from unusual
The low number of reclaimed days contrasts sharply with research suggesting becoming ill while away from work is relatively common.
A Protime survey published in 2024 found that 59% of Flemish respondents said they had been ill during a holiday at some point.
Separate research published by SD Worx in 2025 found that one in three Flemish small and medium-sized businesses had dealt with employees becoming ill during their holidays.
Among employees who did rearrange affected leave, workers in Flanders recovered an average of five days, while the average in Brussels was three days.
The figures suggest the issue is not simply whether people become ill while away. Knowing what to do when it happens is equally important.
Workers need to act while they are away
Recovering sick holiday days requires more than telling an employer about the illness after returning to work.
Belgium’s Federal Public Service Employment says an employee who becomes unable to work during annual leave must immediately notify their employer.
Workers staying away from their normal residence must also provide the address where they are staying. That can be particularly relevant for employees who become ill while travelling abroad.
A medical certificate must also be submitted in accordance with the applicable requirements.
There is another important distinction. Becoming ill does not automatically extend the original holiday. An employee who wants to take the recovered days immediately after their planned leave must specifically request this.
Why Belgium changed the rules
The reform brought Belgian legislation into line with European requirements concerning workers’ annual leave rights.
Annual leave is intended to give employees genuine time away from work for rest. A period when someone is medically unable to work serves a different purpose, meaning illness should not simply consume the worker’s statutory holiday entitlement.
Belgian employment authorities say that when incapacity for work occurs during annual leave, the affected days can be treated as sickness rather than annual holiday when the necessary conditions are satisfied.
The distinction can have a meaningful effect on someone who has only a limited number of holiday days remaining.
Not every type of leave is necessarily covered
Workers should also check which days they have booked.
The protections concern statutory annual holiday. Additional days provided through an employment contract, seniority arrangements, compensatory leave or other workplace schemes may be governed by different conditions.
Employers therefore have an important role in making their procedures clear, particularly the requirements for notifying the workplace and submitting a medical certificate.
For employees, the safest approach is to deal with the paperwork when the illness occurs rather than waiting until they are back at work.
What happens next?
The entitlement introduced in 2024 remains available to qualifying Belgian employees, so workers who become ill during statutory annual leave can continue to preserve those days when they meet the required conditions.
The bigger challenge is practical awareness. Evidence from the first years of the system indicates that illness during holidays is considerably more common than formal recovery of lost leave.
For workers heading away, knowing the rules around sick holiday days before travelling could make the difference between keeping their annual leave and losing days they are legally entitled to take later.
