El número de teléfono está en la tarjeta SIM.

In a normal full sentence, Spanish usually needs an article here, so el número de teléfono is the natural way to say the phone number.

Spanish uses definite articles (el, la, los, las) more often than English does. Without el, the sentence would sound incomplete in most contexts, unless it were a note, label, or headline.

Spanish commonly uses noun + de + noun to show relationships like number of phone / phone number.

So:

• número de teléfono = phone number
• literally, number of telephone

This is a very common pattern in Spanish:

• tarjeta de crédito = credit card
• mesa de madera = wooden table
• zapatos de deporte = sports shoes

Because the sentence is talking about location, and location is normally expressed with estar, not ser.

So:

• está en la tarjeta SIM = it is on/in the SIM card

A useful rule:

• ser = identity, origin, description, time, etc.
• estar = location, condition, temporary states

Since the phone number is being located somewhere, está is the correct choice.

Here, está means is.

It is the third-person singular form of estar:

• yo estoy = I am
• tú estás = you are
• él/ella/usted está = he/she/you are

In this sentence, the subject is el número de teléfono, which is singular, so Spanish uses está.

En is the usual preposition for in, on, or at, depending on context.

Here, en la tarjeta SIM means on the SIM card or in the SIM card, depending on how you interpret it in English. Spanish simply uses en.

Examples:

• Está en la mesa = It is on the table
• Está en la caja = It is in the box
• Está en casa = He/She is at home

So en is broader than any one single English preposition.

The gender comes from tarjeta, which is a feminine noun.

• la tarjeta = the card

So when you say tarjeta SIM, the article still agrees with tarjeta, not with SIM:

• la tarjeta SIM

This is very common in Spanish when a foreign word or acronym is attached to a normal Spanish noun.

Yes, very often you can, especially if the context is already clear.

• Está en la SIM = It is on/in the SIM card

People often shorten expressions like this in everyday speech. However, la tarjeta SIM is clearer and better for learners because it gives the full phrase.

They have written accents because Spanish spelling rules require them.

• número
• teléfono

These words are stressed on the third-from-last syllable, which makes them esdrújulas. In Spanish, all esdrújulas always take an accent mark.

So:

• nú-me-ro
• te-lé-fo-no

The accents help show the correct pronunciation and stress.

Pretty much, yes. This sentence is very close to English word order:

• El número de teléfono = The phone number
• está = is
• en la tarjeta SIM = on/in the SIM card

So the structure is:

subject + verb + location

That makes this sentence quite straightforward for English speakers.

No, that changes the meaning.

• El número de teléfono está en la tarjeta SIM = The phone number is on/in the SIM card
• El teléfono está en la tarjeta SIM would mean The phone is on/in the SIM card, which does not make sense

So número de teléfono is one unit meaning phone number, and you should not shorten it to just teléfono if you want the same meaning.

Yes, número de teléfono is completely normal in Spain.

You may also hear:

• número de móvil = mobile number
• número del móvil = the mobile’s number / mobile number, depending on context

But número de teléfono is standard, clear, and correct everywhere in Spanish.

Yes, in this sentence Spanish naturally uses both articles:

• el número de teléfono
• la tarjeta SIM

English sometimes drops articles where Spanish keeps them, but here both are expected.

So the full pattern is:

• El número de teléfono está en la tarjeta SIM.

That sounds natural and complete in Spanish.