Short answer. No, not by itself. The one-year rule in Article 280 converts a casual employee into a regular one. Genuine project employment sits in a separate exception, so length of service alone does not regularise it — what matters is whether the engagement was truly for a defined project.
What the law says
except where the employment has been fixed for a specific project or undertaking the completion or termination of which has been determined at the time of the engagement of the employee
Labor Code, Article 280 — Regular And Casual Employment. Read the full provision →
What the law says
any employee who has rendered at least one year of service, whether such service is continuous or broken, shall be considered a regular employee with respect to the activity in which he is employed
Labor Code, Article 280 — Regular And Casual Employment. Read the full provision →
The one-year rule belongs to casual employment
Article 280 has two paragraphs doing different work. The first sets out who is regular and carves out project and seasonal engagements. The second deals with employment that is casual — not covered by the first paragraph — and then adds the proviso that any employee who has rendered at least one year of service, whether such service is continuous or broken, shall be considered a regular employee with respect to the activity in which he is employed. That proviso attaches to the casual category. A project employee who works eighteen months on a long build is not regularised by the calendar alone.
What makes an engagement a project engagement
The exception applies where the employment has been fixed for a specific project or undertaking the completion or termination of which has been determined at the time of the engagement of the employee. Two things must be true, and both at the start. The project has to be specific, so that everyone can say what it is and when it ends; and its completion or termination has to have been determined when you were hired, not decided later when the employer wanted the engagement over. A contract naming no project, or one that describes your duties in general terms, does not meet this.
The label in your contract does not settle it
The article opens by binding the parties regardless of what they wrote down: the provisions of a written agreement to the contrary notwithstanding, and regardless of any oral agreement. So being handed a document headed project employment contract proves nothing on its own. If in truth you were doing work usually necessary or desirable in the employer's ordinary business, with no identified project and no end determined at engagement, the first paragraph makes you regular from the outset, and the question of one year never arises.
What to look at in your own case
Line up the contracts you signed and read what each one names as the project. Successive contracts covering the same continuous work, each naming a different or vaguely described undertaking, with no gap between them, tell a different story from a genuine series of separate builds. Note whether you were reassigned to other sites when a project ended, and whether your work is what the company does day in and day out. Those facts, not the heading on the paper, decide which paragraph of the article you fall under.