Partimos mañana.

It comes from partir, an -ir verb.

In this sentence, partimos means we leave / we depart.

A few forms of partir:

• yo parto = I leave
• tú partes = you leave
• él/ella parte = he/she leaves
• nosotros/nosotras partimos = we leave
• vosotros/vosotras partís = you all leave
• ellos/ellas parten = they leave

In Spain, partir can sound a bit more formal or literary than salir in some contexts, but it is perfectly correct.

Because Spanish often uses the present tense to talk about a planned or scheduled future action, just like English can do in sentences such as We leave tomorrow.

So Partimos mañana literally uses the present, but its meaning is future because mañana makes the time clear.

This is very common in Spanish:

• Llegamos el lunes = We arrive on Monday
• Salgo en una hora = I’m leaving in an hour
• Empezamos mañana = We start tomorrow

Yes. Partimos can mean either:

• we leave / are leaving (present)
• we left (preterite / simple past)

For some -ir verbs, the nosotros form is the same in the present and the preterite.

So:

• Partimos mañana = clearly we leave tomorrow
• Partimos ayer = clearly we left yesterday

The time word usually tells you which meaning is intended.

Because Spanish usually drops subject pronouns when they are not needed.

The ending -imos already tells you the subject is we.

So:

• Partimos mañana = normal, natural
• Nosotros partimos mañana = also correct, but more emphatic

You might include nosotros if you want contrast or emphasis:

• Ellos se quedan, pero nosotros partimos mañana.
  = They are staying, but we leave tomorrow.

They are similar, but not always identical.

• salir often means to go out / to leave / to set off
• partir often means to depart / to leave, and can sound a bit more formal, narrative, or travel-related

In many travel contexts, both can work:

• Salimos mañana
• Partimos mañana

But salir is often more common in everyday speech.

Also, partir has other meanings in other contexts, such as to split / divide / break:

• Partir una manzana = to cut/split an apple

So context matters.

Here it means tomorrow.

That is because the whole sentence is about the time of departure:

• Partimos mañana = We leave tomorrow

But mañana can also mean morning in other contexts:

• por la mañana = in the morning
• esta mañana = this morning

So mañana has two meanings:

• tomorrow
• morning

The context tells you which one is meant.

Yes. Spanish word order is flexible.

These are all possible:

• Partimos mañana
• Mañana partimos

Both mean the same basic thing. The difference is mainly one of emphasis or style:

• Partimos mañana focuses first on the action
• Mañana partimos puts the time first

Both sound natural.

A simple pronunciation guide is:

• partimos ≈ par-TEE-mos
• mañana ≈ ma-NYA-na

A few points:

• In partimos, the stress is on ti
• The ñ in mañana sounds like the ny in canyon
• In standard Spain Spanish, mañana is pronounced with a clear ny sound: ma-NYA-na

Yes, they could. It is correct and natural.

That said, in everyday conversation, many speakers might more often say:

• Nos vamos mañana = We’re leaving tomorrow
• Salimos mañana = We leave tomorrow

Partimos mañana is still perfectly good Spanish, but depending on context it can sound:

• a little more formal
• a little more travel-related
• a little more like depart than casual leave

Not necessarily. Just like in English, we can be:

• inclusive: including the listener
• exclusive: not including the listener

The sentence by itself does not tell you which one is meant.

For example:

• speaking to a friend who is travelling with you: Partimos mañana
• speaking to someone staying behind: Partimos mañana

Only the context tells you who is included.

Yes. Vamos a partir mañana is grammatically correct and means we are going to leave tomorrow.

However, in real speech, many people would more naturally say:

• Vamos a salir mañana
• Nos vamos mañana

Compared with Partimos mañana:

• Partimos mañana = simple, direct, often very natural for scheduled plans
• Vamos a partir mañana = more explicitly future-oriented, but sometimes less common in everyday speech with partir

Yes, but the difference is small.

• Partimos mañana = present used for a planned future action
• Partiremos mañana = future tense, we will leave tomorrow

Both are correct.

In everyday Spanish, the present for near future plans is very common:

• Partimos mañana

The future form can sound a bit:

• more formal
• more definite
• sometimes more written or rhetorical, depending on context

So in ordinary conversation, Partimos mañana is often very natural.