The verb "ser" (to be: soy, eres, es...)

Yo soy profesor. Ella es de México.I am a teacher. She is from Mexico.

ser is one of Spanish's two verbs for "to be" — this lesson is about its own forms and its own typical jobs. (Spanish's other "to be," estar, covers different ground; comparing the two is its own lesson once you know both.)

Quick shortcut: soy (I am), eres / sos (you are, informal — sos with vos), es (he/she/it is, you are formally), somos (we are), sois (you all are, Spain), son (they/you all are).

Conjugation

ser is irregular — none of these forms come from a predictable pattern, so they're worth memorizing as a block. Note that usted and él/ella share es, and ustedes and ellos/ellas share son — the same pattern every verb follows for these subjects.

Identity: who or what someone is

ser names what something fundamentally is — a profession, a role, a category:

• Soy profesor. (I am a teacher.)
• Es mi hermana. (She is my sister.)
• Madrid es una ciudad. (Madrid is a city.)

Origin and nationality

ser de + place says where someone or something is from:

• Soy de Argentina. (I am from Argentina.)
• Somos de aquí. (We are from here.)

Nationality adjectives work the same way, without de:

• Es mexicana. (She is Mexican.)

Characteristics

ser + an adjective describes a trait that's felt as a basic, defining quality of the person or thing — physical appearance, personality, or an inherent property:

• Ella es alta. (She is tall.)
• Él es muy inteligente. (He is very intelligent.)
• El café es amargo. (Coffee is bitter.)

This is exactly the point where Spanish's other "to be," estar, also comes in — for a temporary state rather than a defining trait (Él está cansado, "He is tired," right now). Telling the two apart is its own lesson: ser vs estar: basic contrast.

Time and dates

ser tells time and gives the day, date, or season:

• Son las tres. (It's three o'clock.) — but Es la una. (It's one o'clock.), since una is singular
• Hoy es lunes. (Today is Monday.)
• Es verano. (It's summer.)

Material and possession

ser de also says what something is made of, or who it belongs to:

• La mesa es de madera. (The table is made of wood.)
• Este libro es de Juan. (This book is Juan's.)

Common mistakes

• ❌ Yo soy 25 años. → ✅ Yo tengo 25 años. (age uses tener, "to have," not ser — a common calque from languages that use "to be" for age)
• ❌ Son las una. → ✅ Es la una. (one o'clock is singular — son is for every other hour)
• ❌ Ella está profesora. → ✅ Ella es profesora. (identifying someone's profession is ser; estar de profesora exists but means working temporarily as one, not the same statement)
• ❌ Mixing up es and son: Ellos es de Perú. → ✅ Ellos son de Perú. (match the verb form to the subject, not just to "he/she" vs "they")

Quick check

Which form fits?

1. Yo ____ de Colombia. (soy / eres)
2. Nosotros ____ amigos. (somos / son)
3. ¿Qué hora es? — ____ las cinco. (Es / Son)
4. Este coche ____ de mi padre. (soy / es)
5. Vosotros ____ muy generosos. (sois / son)

Key takeaways

• ser conjugates irregularly: soy, eres (sos), es, somos, sois, son.
• Use it for identity (profession, role), origin and nationality, defining characteristics, telling time and dates, and material or possession (ser de).
• Age uses tener, not ser — a frequent mistake for speakers of languages that use "to be" for age.
• One o'clock is es la una; every other hour is son las....
• Telling ser apart from Spanish's other "to be," estar, for describing traits vs. states is its own lesson.