Short answer
Under the Working Time Directive, a period is either working time or rest; there is no intermediate EU category. Time is working time when the worker is working, at the employer's disposal and carrying out duties. The Court interprets those elements together and focuses on the worker's objective constraints.
On-call duty at a workplace or another place fixed by the employer is normally working time in full, including inactive or sleeping periods. Standby elsewhere, with only a duty to remain reachable, is working time in full only where employer-imposed constraints objectively and very significantly restrict the worker's ability to use the inactive time freely. Actual call-outs are always working time.
Travel from home to the first customer and from the last customer home counts for workers with no fixed workplace where the employer assigns the route. Employer-required vocational training counts even outside normal hours and away from the usual workplace. Actual remote work counts; mere after-hours reachability follows the standby test. Classification under the Directive protects rest and maximum hours but does not, by itself, decide how each period must be paid.
The Directive's binary test
Article 2(1) of defines working time as:
any period during which the worker is working, at the employer's disposal and carrying out his activity or duties, in accordance with national laws and/or practice. —
A rest period is any period that is not working time. National law cannot create a third category that removes a period from both. The concepts are autonomous EU-law concepts, although national law determines employment status and can give workers more protection.
Classification matters because the Directive generally requires 11 hours of daily rest, weekly rest, breaks and an average 48-hour maximum week. Derogations must meet its conditions and usually require compensatory rest.
On-call duty at a required place is working time in full
The clearest rule concerns physical presence. In SIMAP, the Court distinguished doctors required to remain at a health centre from doctors merely contactable elsewhere:
Time spent on call ... must be regarded in its entirety as working time ... if they are required to be at the health centre. If they must merely be contactable at all times when on call, only time linked to the actual provision of ... services must be regarded as working time. —
In Jaeger, C-151/02, the Court confirmed that hospital on-call duty remains working time in full even when the doctor may sleep or rest during inactivity. The employer has required presence and immediate availability at its chosen place; the intensity of work does not change classification.
The “place” need not be the normal workplace. A duty to stay at home can have the same effect if coupled with severe response constraints. In Matzak, C-518/15, a firefighter had to remain at home and respond within eight minutes. That combination very significantly restricted other activities, so the entire standby period was working time.
Reachable standby away from a fixed place requires an overall assessment
Being required to carry a phone or answer messages does not automatically convert every hour into working time. Where the worker may choose their location, the question is whether constraints imposed by law, collective agreement or the employer objectively and very significantly impair free management of inactive time.
Relevant factors are:
- the response time and what it practically requires;
- how often calls normally occur and how long interventions last;
- required equipment, clothing or travel before responding;
- geographical limits or required location; and
- whether personal activity can realistically be planned.
The Court expressed the test in Radiotelevizija Slovenija, C-344/19:
[A standby period is working time in its entirety only where] the constraints imposed on that worker ... affect, objectively and very significantly, the latter's ability freely to manage ... the time during which his or her professional services are not required and to devote that time to his or her own interests. —
A one-hour return time and optional employer accommodation did not automatically satisfy that test; the national court had to consider the whole picture, including average call frequency. By contrast, Matzak's eight-minute deadline and home-presence obligation did.
Only constraints attributable to the employer, collective rules or legislation count in this assessment. Natural isolation, limited leisure facilities or the worker's personal choice to live far away normally do not. If the whole standby period does not qualify, time actually spent answering, working or travelling on a call-out still does.
Working time and remuneration are different questions
The Working Time Directive is a safety-and-health measure. Except for paid annual leave, it generally does not harmonise remuneration. Matzak expressly held that EU law does not require standby pay to follow its classification as working or rest time.
National law and agreements may pay inactive on-call time differently. But a lower rate does not exclude working hours from rest or the 48-hour ceiling.
When travel is working time
Ordinary commuting to a fixed workplace is not converted into working time merely because employment requires attendance. The result changes for genuinely mobile workers whose employer has removed the fixed base and assigns the day's customers.
In Tyco, technicians travelled directly from home to customers and home after the final appointment. The employer determined the customers and routes, and travelling was integral to performing installations and maintenance:
[W]here workers do not have a fixed or habitual place of work, the time spent by those workers travelling each day between their homes and the premises of the first and last customers designated by their employer constitutes ‘working time’. —
This does not make every commute working time. Ask whether there is no fixed workplace, travel is inherent in duties, and the employer controls destinations. Travel between customers is ordinarily working time; temporary-assignment travel remains fact-specific.
In Obras y Servicios Públicos, C-110/24, required group journeys from an employer-selected base to the work site also counted. The employer fixed the time, place and vehicle, leaving workers unable to use the journey freely. That differs from an ordinary commute.
Employer-required training is working time
In Case C-909/19, a municipal worker attended 160 hours of vocational training requested by the employer, outside normal hours, away from the usual workplace and performing different activities. The Court held:
[T]he period during which a worker attends vocational training required by his or her employer ... constitutes ‘working time’ within the meaning of that provision. —
The employer's instruction and the worker's obligation to attend were decisive; neither location nor the fact that training differed from normal duties changed the result. Voluntary study chosen by the worker, without an employer requirement, is not resolved by that holding and may depend on national law and the actual employment obligation.
Remote work and after-hours contact
Remote work does not alter Article 2. Time spent performing assigned tasks, attending virtual meetings, answering required communications or otherwise working at the employer's disposal is working time whether at home or elsewhere. A flexible schedule changes when the work occurs, not whether actual work counts.
Mere reachability must be separated from actual work. A light requirement to keep a phone available, with infrequent contacts and generous response time, may leave the inactive period as rest. A duty to monitor continuously, respond almost immediately, remain near equipment, or handle frequent calls may satisfy the Radiotelevizija test for the whole period. Each actual intervention counts even if the overall standby period does not.
Member States must require an objective, reliable and accessible system enabling daily working time to be measured, as the Grand Chamber held in CCOO, C-55/18. For remote and mobile work, that means a system capable of capturing actual work and qualifying standby without treating uninterrupted surveillance as the only solution. Data-protection, proportionality and national consultation rules remain relevant.
A practical classification method
For each disputed period, record the required location, response deadline, normal intervention frequency, duration, travel, equipment and freedom to pursue personal activity. Then ask:
- Was the worker actually performing work or required training? If so, it is working time.
- Did the employer require presence at a determined place? The entire period is normally working time.
- If only reachable, do employer-imposed constraints objectively and very significantly restrict free time? If yes, the whole period counts; if no, interventions count.
- Is travel integral to duties for a worker without a fixed workplace and directed by the employer? If yes, Tyco applies.
- Do the recorded hours preserve daily and weekly rest and the average weekly ceiling?
Conclusion
EU working-time law focuses on control and practical freedom, not labels. Required workplace presence counts in full; reachability elsewhere depends on employer-imposed constraints. Mobile-worker travel and required training can count outside conventional hours or premises. Employers need reliable records and must assess pay separately while counting all EU working time for rest and maximum-hours protection.
Sources
This article provides general legal information, not advice for a specific matter. Laws, facts and procedural deadlines may change the result. Follow the linked primary sources and obtain local advice before acting.