According to El Español - Alicante, workers hired on a temporary contract of up to six months (inclusive) generally cannot be given a trial period of more than one month.

This limit can be changed by a collective agreement (convenio colectivo), which is entitled to set a different period. Trial periods are governed by article 14 of the Workers' Statute (Estatuto de los Trabajadores). The period must be agreed in writing and must stay within the limits set by collective agreements.

Where no collective agreement says otherwise, the maximum is six months for técnicos titulados (the source does not explain the term) and two months for all other staff. At companies with fewer than 25 employees, the limit for staff who are not técnicos titulados is three months. This does not override the special rule for temporary contracts of up to six months.

During the trial period the worker keeps the rights and obligations that go with the post, as any other member of staff would. Either side can end the employment relationship on its own initiative. An employer's decision to end it with a pregnant worker, or one in a maternity situation, is void unless the reasons have nothing to do with pregnancy or maternity.

A new trial period cannot be set for someone who has already done the same duties at that company, whatever type of contract they had. Such an agreement is void. If the period runs out and neither side has ended the relationship, the contract applies in full and the time worked counts towards length of service with the company. The trial-period clock stops during temporary incapacity for work, birth, adoption, guardianship with a view to adoption, foster care, risk during pregnancy, risk during breastfeeding and gender-based violence, but only if both sides agree to this.

The source's headline says the rule has "entered into force", but the article does not give a date, name the law, or say whether this is a new change. It also cites no official source such as the BOE (Spain's official state gazette) or the Ministry of Labour.