The employment relationship is based on an employment contract based on indefinitely. An employment contract can exceptionally be concluded on specific time, for the establishment of an employment relationship, the termination of which is determined in advance by objective reasons that are justified by the deadline, the execution of a certain job or the occurrence of a certain event.
The Labor Law limits the duration of a fixed-term employment contract to an uninterrupted period of no longer than 3 years, and an interruption of less than two months is not considered an interruption of the three-year period.
Contract of employment is concluded in writing. The failure of the contracting parties to conclude an employment contract in writing does not affect the existence and validity of that contract. If the employer does not conclude a written employment contract with the employee before starting work or does not issue him a written confirmation of the concluded contract, he is considered to have concluded an employment contract with the employee for an indefinite period.
Labor Law as the lowest age limit stipulates the age of fifteen (15) for concluding an employment contract, and in this sense prescribes that a person under fifteen or a person aged fifteen and over fifteen, and under eighteen who attends compulsory elementary education, may not be employed.
The Labor Law also regulates the issue trial work in such a way as to prescribe how trial work can be contracted when concluding an employment contract. Trial work may not last longer than six months. If trial work is contracted, the notice period is at least seven days. Dissatisfaction with a probationary employee is a particularly justified reason for terminating the employment contract.
Source: https://investcroatia.gov.hr/zaposljavanje/sadrzaj-ugovora-o-radu/