Is it compulsory to give my e-mail address and personal telephone number to the company?

If a company requires an employee to give it a personal email address and telephone number, is it legal? A recent Supreme Court ruling allows a company to require an employee to provide a personal email and telephone number, in certain very specific cases. In this article we analyse what the law says and what the courts say about this aspect.

What do the regulations say on this subject?

In relation to e-mail and personal telephone in relation to the company where a person works, we must consider two essential regulations:

- Personal and Data Protection Act and guarantee of digital rights.

This regulation refers to several important aspects (which relate to the General Data Protection Regulation at European level):

• Principle of data minimisation. It must be ensured that only data strictly necessary for the specific purposes are processed. Therefore, only data that are necessary to fulfil the legitimate purposes of the employment relationship may be collected. It must be assessed whether the personal telephone number and personal e-mail are essential for the employee to fulfil his or her work duties. 
• Right to digital disconnection. This right ensures that outside of working time, whether devoted to rest, leave or holidays, workers have the right to digital disconnection.

- General Data Protection Regulation.

It regulates the cases in which data processing is legitimate and establishes that it will be legitimate if several conditions are met, such as the following: ‘processing is necessary for the performance of a contract to which the data subject is party or for the implementation at his request of pre-contractual measures’.

- Workers' Statute.

It establishes, among the basic duties of workers, to comply with the specific obligations of their job, in accordance with the rules of good faith and diligence.

- Law on remote work.

Article 17.2 stipulates that the company may not require the installation of programmes or applications on devices owned by the worker, nor the use of these devices in the performance of remote work.

But is it permissible for the company to require an employee to have a mobile phone or personal email? Let's see what the Supreme Court says.

The Supreme Court holds that employees are not obliged to give their personal mobile phone or email to the company.

In 2015, the Supreme Court analysed a case in which a company included a clause in its employment contracts stating the following: "both parties expressly agree that any type of communication relating to this contract, the employment relationship or the job position may be sent to the worker via SMS or email, by means of a text message or document attached to the same, depending on the details provided by the worker for contact purposes . Any change or incident with respect to the same must be communicated to the company in a reliable manner and as soon as possible".

The Supreme Court accepts that such data may be made available to the company on a voluntary basis, but opposes the inclusion of a standard clause whereby the worker consents to the processing and use of such personal data.

In this case, the Supreme Court considers that the data included in the contract (mobile phone and e-mail) are not exempt from the worker's consent because they are not necessary for the performance of the employment contract.

In 2024, the Supreme Court analysed another case in which a company managed 80% of its workforce in teleworking mode and required workers to provide a personal email for work procedures. However, in these cases, the telecommuting law considers e-mail as an essential means to carry out the activity and the company must provide it, therefore, the ruling states that it is not valid for the company to force workers to use their personal e-mail for work matters, nor is it valid for it to include text in the employment contracts. It is understood that it violates the fundamental rights to privacy and data protection.

Are there cases in which it is legitimate for the employer to demand the employee's personal email and mobile phone?

The answer is yes, but the case must be analysed carefully to see the particularity. This is a Supreme Court ruling of April 2025 (STS 1514/2025 of 2 April 2025) which analyses a case in which a company used a standard remote work contract in which it established that the worker would provide the company with his email address and personal telephone number in case it was necessary to contact him due to service emergencies. In addition, it established that the worker will have the right to digital disconnection when his or her working day has ended, unless there are justified emergency circumstances. It is considered that there are circumstances of justified urgency and that you are going to have a business or business detriment whose temporary urgency requires an immediate response or attention from the worker.

Initially, the case was analysed by the Audiencia Nacional, which considered null and void the clause establishing the employee's obligation to provide the company with his personal email and mobile phone, in case it was necessary to contact him due to service emergencies.

In this case, the Supreme Court overturns the National Court's ruling and considers several issues:

• The email and personal mobile phone may be additionally necessary for the performance of the employment contract.
• These means can only be used by the company in cases of service urgency.

Therefore, based on the above, the key is whether these means (personal telephone and mail) are necessary for the performance of the employment contract or not and whether they will be used only in case of urgency of service. If they are not necessary, the clause requiring them may be declared null and void.

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