Camminiamo per un chilometro.

Camminiamo is the 1st person plural form of camminare (to walk).

So it can mean:

• we walk
• we are walking
• sometimes let’s walk, depending on context

Italian present tense often covers both the simple present and the present continuous idea that English separates.

Yes. That is a very common question.

Camminiamo can be:

• indicative present: we walk / we are walking
• 1st person plural imperative-like suggestion: let’s walk

So Camminiamo per un chilometro could mean either:

• We’re walking for a kilometer
• Let’s walk for a kilometer

Usually the broader context tells you which meaning is intended.

Italian often drops subject pronouns when they are not needed.

Since camminiamo already clearly means we, adding noi is usually unnecessary.

• Camminiamo per un chilometro. = We walk / We are walking for a kilometer.
• Noi camminiamo per un chilometro. = still correct, but more emphatic, like we walk for a kilometer.

So the version without noi is the normal, natural one.

Here per means something like for in the sense of over a distance of.

So:

• per un chilometro = for one kilometer

It does not mean through here.

In this sentence, per expresses the distance covered.

Italian uses:

• un before most masculine singular nouns
• uno before masculine singular nouns beginning with certain sounds, such as z, s + consonant, gn, ps, x, etc.

Since chilometro begins with a normal c sound, you use un:

• un chilometro

Compare:

• un libro
• un ragazzo
• uno studente

So uno chilometro would be incorrect.

Because it follows un, which means one.

So:

• un chilometro = one kilometer
• due chilometri = two kilometers

Just like in English, one kilometer uses the singular.

In this sentence, it refers to distance, not time.

• Camminiamo per un chilometro. = We walk for a distance of one kilometer.

Even though English for often makes learners think of time, here it is about how far you walk.

Yes, you may hear Camminiamo un chilometro, and it can sound natural.

But per un chilometro makes the idea of distance covered especially clear.

So:

• Camminiamo per un chilometro.
• Camminiamo un chilometro.

Both can work, but per is very common and explicit in this kind of sentence.

Because the verb is camminare, spelled with mm.

Its stem is cammin-, so the form becomes:

• cammin- + -iamo = camminiamo

That double consonant is part of the normal spelling of the verb, so it should be kept in all related forms:

• cammino
• cammini
• cammina
• camminiamo

A simple English-friendly approximation is:

• kahm-mee-NYAH-mo

A few points:

• the mm is pronounced clearly
• niamo sounds like nyah-mo
• the stress falls on -nia-: cammiNIAMO

And chilometro is roughly:

• kee-loh-MEH-tro

So the whole sentence is approximately:

• kahm-mee-NYAH-mo per oon kee-loh-MEH-tro

Not exactly.

• camminare = to walk
• andare = to go

So camminare focuses on the action of walking itself.

For example:

• Camminiamo per un chilometro. = We walk for a kilometer.
• Andiamo al parco. = We’re going to the park.

Sometimes English uses go where Italian prefers walk, and vice versa, so it is useful to keep the distinction in mind.

Yes, it is a natural sentence.

It could be used in contexts like:

• discussing exercise
• describing a route
• planning a walk
• giving instructions or making a suggestion

For example:

• Camminiamo per un chilometro e poi ci fermiamo.
  We walk for a kilometer and then we stop.

So the sentence is short, simple, and perfectly normal Italian.