Calling a legal strike: notification, notice period and minimum services

The strike is a fundamental right recognised in article 28.2 of the Constitution. Its exercise is regulated by Real Decreto-ley 17/1977, de 4 de marzo, sobre relaciones de trabajo, as refined by the Constitutional Court in ruling 11/1981. There is still no organic strike law, so this text, interpreted by the Constitutional Court, remains the reference standard in 2026.

Three subjects can agree to declare a strike: workers' representatives (works council or personnel delegates) by majority decision, trade unions established in the area of the conflict (a power recognised by STC 11/1981 and consistent with the Ley Orgánica de Libertad Sindical) and the workers themselves directly, through a majority agreement adopted in an assembly. The requirement for this vote to be secret appeared in article 3.2.b) of RDL 17/1977, but STC 11/1981 declared that clause unconstitutional: the assembly agreement is valid even if adopted by a show of hands, provided the majority is proven.

The agreement must be documented: minutes of the meeting of the convening body or assembly, the voting result and the affected scope (company, workplace, sector or territory). These minutes form the basis of the subsequent formal notification.

The call is communicated in writing and in duplicate: to the affected employer or employers and to the competent labour authority. The minimum notice period is 5 calendar days before the start date (articles 3 and 4 of RDL 17/1977). If the strike affects companies in charge of any kind of public services, the notice period rises to 10 calendar days and the conveners must also publicise the call so that service users are aware of it.

STC 11/1981 itself admits an exception to this period: in justified cases of force majeure or state of necessity, the conveners may be exempted from respecting the legal notice period. This is an exceptional way out and you must be able to prove the circumstance that justifies it, so the practical rule remains to comply with the 5 or 10 days.

The document must obligatorily contain the objectives of the strike, the steps taken to resolve the differences, its start date and the composition of the strike committee. The committee cannot exceed 12 members and must be made up of workers from the area affected by the conflict (article 5). A defect in any of these points can make the strike illegal.

The competent labour authority depends on the scope: the regional ministry with labour competencies of the autonomous community if the strike does not exceed it, or the Directorate General of Labour of the Ministry if it affects workplaces in several communities. The notification itself does not carry a tasa (official fee), as it involves the exercise of a fundamental right. Managora identifies the competent authority, drafts the notification with all the requirements and submits it on time; you can check the service conditions in the procedure file.

It is advisable not to confuse two concepts. Security and maintenance services (article 6.7 of RDL 17/1977) operate within any company: the strike committee must guarantee during the strike the necessary services for the safety of people and property, the maintenance of premises, machinery and facilities and the subsequent resumption of activity.

Minimum services strictly speaking only apply in strikes affecting essential community services (health, transport, energy, communications). They are set by the governmental authority (Government or autonomous community) under article 10.2 of RDL 17/1977, through a resolution that must be reasoned and proportionate: it cannot empty the right to strike of its content. This resolution can be appealed before the contentious-administrative jurisdiction.

A worker designated to cover minimum or maintenance services who fails to comply with them can be sanctioned. The rest of the workforce keeps their right to support or not support the strike intact.

Article 11 of RDL 17/1977 declares four types of strike illegal: political strikes or those unrelated to the professional interest of the workers, solidarity strikes that do not affect the professional interest of those supporting them, strikes intended to alter what was agreed in a collective agreement in force (novatory strike) and those called in contravention of the requirements of the Real Decreto-ley itself, for example without notice or without notification to the labour authority.

STC 11/1981 qualified this list: a protest strike against socioeconomic policy decisions affecting workers' interests is possible, solidarity is admitted when there is a connection with the professional interest, a strike during the validity of the agreement is possible if an interpretation of what was agreed is claimed or circumstances have changed substantially, and failure to comply with the notice period is excused in cases of force majeure or state of necessity.

Furthermore, article 7.2 presumes rotating strikes, strategic or bottleneck strikes (stoppages in key sectors to interrupt the entire production process), work-to-rule strikes and any collective alteration of work other than a strike to be abusive. Following STC 11/1981, this presumption admits proof to the contrary. The illegal occupation of the workplace is also prohibited (article 7.1).

No. Article 6.5 of RDL 17/1977 prohibits the employer from replacing strikers with workers who were not linked to the company at the time the strike was communicated (external strikebreaking). Nor can they be covered with workers from temporary employment agencies. Case law extends the prohibition to internal strikebreaking: moving workers from another workplace, shift or category to neutralise the effects of the strike.

Regarding technological strikebreaking, the doctrine has changed in 2026. STC 17/2017 had allowed the company to use already existing technical means during the strike; STC 24/2026, de 12 de marzo (published in the BOE on 14 April 2026), corrects this doctrine in the Metro de Sevilla case: using the technical, technological or organisational means available to the company to neutralise the strike (there, putting double-composition trains into circulation during the stoppages) violates article 28.2 CE.

Dismissal or sanction for exercising the right to a legal strike is null and void. Conversely, active participation in an illegal strike can indeed have disciplinary consequences.

During a legal strike, the employment contract is suspended (article 45.1.l of the Estatuto de los Trabajadores): the worker does not provide services and the company does not pay a salary. The deduction covers the salary for the strike days and the proportional part of the extraordinary payments and the weekly rest for the period, according to consolidated case law.

In the Seguridad Social (the Spanish social security system), the striker moves to a special active status: neither the company nor the worker contributes for the strike days. Healthcare is maintained, but there is no right to unemployment benefits for that period or to the temporary disability subsidy if the sick leave begins during the strike. To avoid contribution gaps, the worker can sign a special agreement with the Seguridad Social.

If you are going to call a strike, the real risk lies in formal defects: a short notice period, a committee of more than 12 members or an incomplete notification can make it illegal. Managora drafts the official notification with all the requirements of RDL 17/1977, determines the applicable notice period (5 or 10 calendar days) and submits it to the company and the competent labour authority. You can check the service conditions in the strike call notification procedure file.