El puente fue construido por los romanos.The bridge was built by the Romans.

Spanish has a passive voice built with ser + past participle, close in structure to the English passive. It lets the receiver of an action be the subject of the sentence, and — unlike passive se — it can name who performed the action.

Quick shortcut: ser (conjugated in the tense of the action) + past participle (agreeing in gender and number with the subject), optionally + por + agent. El puente fue construido por los romanos. This construction is mostly formal or written — everyday spoken Spanish usually prefers the active voice or se.

Building the passive: ser + participle, agreeing with the subject

Only transitive verbs can normally form this passive: the verb's direct object becomes the subject of the passive sentence, so an intransitive verb like llegar ("to arrive") has nothing to promote and can't be passivized this way (there's no fue llegado). With a transitive verb, conjugate ser in whatever tense the action happened in, and make the past participle agree in gender and number with the subject — just like an adjective:

La casa fue construida en 1950. (The house was built in 1950 — feminine singular subject and participle.) Los puentes fueron construidos por los romanos. (The bridges were built by the Romans — masculine plural.) Las cartas fueron escritas ayer. (The letters were written yesterday — feminine plural.)

This agreement is the biggest difference from the participle used in compound tenses like the present perfect (ha construido), where the participle never changes. Here, because it's functioning like an adjective describing the subject, it agrees just like one.

Naming the agent with por

Unlike passive se, the ser passive can freely name who or what performed the action, introduced by por:

El puente fue construido por los romanos. (The bridge was built by the Romans.) La novela fue escrita por Cervantes. (The novel was written by Cervantes.)

The agent is optional — you can also leave it out, just like in English ("The bridge was built in the third century"):

El puente fue construido en el siglo III. (The bridge was built in the third century.)

Present and preterite, and how common this is

The ser passive can technically appear in any tense, but this article focuses on the two most common: the present, for things that are habitually or generally true, and the preterite, for a single completed event:

La ciudad es visitada por miles de turistas cada año. (The city is visited by thousands of tourists every year — present, a general truth.) El museo fue inaugurado en 1980. (The museum was inaugurated in 1980 — preterite, one completed event.)

In everyday conversation, Spanish speakers reach for this construction less often than English speakers reach for the passive — the active voice, or passive/impersonal se, is usually more natural. The ser passive is common in news writing, formal reports and historical narration, especially when the agent needs to be named.

Ser + participle vs. estar + participle

Estar + participle describes the resulting state after an action, not the action itself:

La puerta fue cerrada a las nueve. (The door was closed at nine — the event of closing it, by someone, at that moment.) La puerta está cerrada. (The door is closed — the resulting state, right now, regardless of who closed it or when.)

If you're describing the event of something happening, use ser. If you're describing the state something is in afterward, use estar.

Common mistakes

  • ❌ La casa fue construido en 1950. → ✅ La casa fue construida en 1950. (the past participle must agree in gender and number with the subject — casa is feminine, so construida, not construido.)
  • ❌ El puente fue construido de los romanos. → ✅ El puente fue construido por los romanos. (the agent in a ser passive is introduced by por, not de.)
  • ❌ La puerta fue cerrada ahora mismo (meaning it's currently in a closed state) → ✅ La puerta está cerrada. (describing a current resulting state calls for estar + participle, not ser + participle, which describes the event itself.)

Quick check

  1. Complete: Las ventanas ___ (fue/fueron) reparadas ayer.
  2. Complete: El libro fue escrito ___ (de/por) un autor famoso.
  3. Why is La mesa fue hecho de madera wrong?
  4. Contrast: what's the difference between El museo fue cerrado a las seis and El museo está cerrado?
Show answers
  1. Las ventanas fueron reparadas ayer.
  2. El libro fue escrito por un autor famoso.
  3. The participle must agree with the subject mesa (feminine): it should be hecha, not hecho — La mesa fue hecha de madera.
  4. Fue cerrado describes the event of closing at six o'clock; está cerrado describes the museum's current state, regardless of when it was closed.

Key takeaways

  • The ser passive = ser conjugated in the tense of the action + a past participle agreeing in gender and number with the subject.
  • The agent, if named, is introduced with por: construido por los romanos.
  • It's mostly formal or written; everyday speech usually prefers the active voice or se.
  • Ser + participle describes the action/event; estar + participle describes the resulting state afterward.