Prima che la raccomandata parta, controllo che il CAP del destinatario sia giusto.

Because after prima che, Italian normally uses the subjunctive.

• parte = present indicative of partire
• parta = present subjunctive of partire

So:

• Prima che la raccomandata parte ❌
• Prima che la raccomandata parta ✅

This happens because prima che introduces something that has not happened yet at the moment of the main action, so Italian treats it as uncertain, pending, or not yet realized.

For the same basic reason: controllare che often takes the subjunctive when what follows is something being checked, verified, or evaluated rather than simply stated as a fact.

• è = indicative
• sia = subjunctive

So:

• Controllo che il CAP del destinatario è giusto sounds non-standard in careful Italian.
• Controllo che il CAP del destinatario sia giusto is the expected form.

The idea is: I check whether / that the ZIP code is correct, so the correctness is something being verified.

In standard Italian, yes, prima che is followed by the subjunctive.

Examples:

• Ti chiamo prima che tu parta.
• Andiamo via prima che piova.
• Prima che arrivino gli ospiti, preparo tutto.

This is one of the most useful fixed patterns to memorize:

prima che + subjunctive

Because the sentence contains two different subordinate clauses, and each one is introduced by che.

1. Prima che la raccomandata parta
   = Before the registered letter is sent / leaves

2. controllo che il CAP del destinatario sia giusto
   = I check that the recipient’s ZIP code is correct

So the full sentence is built like this:

• Prima che... = time clause
• controllo che... = object/content clause

It may look repetitive in English, but in Italian this is completely normal.

Because the subject of the subordinate clause is different from the subject of the main clause.

Main clause:

• controllo = I check

Subordinate clause:

• il CAP del destinatario sia giusto = the subject is il CAP

When the subject changes, Italian usually uses a full clause with che + finite verb, not an infinitive.

Compare:

• Controllo di avere tutto.
  I check that I have everything.
  Same subject: I → infinitive is possible.

• Controllo che il CAP sia giusto.
  Different subject: I / the ZIP code → finite clause needed.

Here la raccomandata means registered mail or a registered letter.

It is a common false friend for English speakers, because it looks like recommended or recommendation, but that is not the meaning here.

Useful related words:

• una lettera = a letter
• una raccomandata = a registered letter / registered mail item
• spedire una raccomandata = to send registered mail

So in this sentence, it refers to a postal item, not advice or a recommendation.

CAP stands for Codice di Avviamento Postale, which is the Italian postal code or ZIP code.

So:

• il CAP = the postal code / ZIP code

It is normally written in capitals because it is an acronym.

Examples:

• Qual è il tuo CAP?
• Ho sbagliato il CAP.

Italian uses definite articles more often than English does.

So where English might say:

• Check ZIP code

Italian often prefers:

• controllare il CAP

Here il CAP del destinatario means the recipient’s ZIP code.

Including the article sounds natural and standard in Italian.

Del destinatario means of the recipient.

It is made of:

• di = of
• il = the
• del = contraction of di + il

So:

• il CAP del destinatario = the recipient’s ZIP code
  literally, the ZIP code of the recipient

Destinatario is the person who receives something.

Related word:

• mittente = sender

So in postal language:

• destinatario = recipient/addressee
• mittente = sender

Yes, corretto would also work.

• giusto = right, correct
• corretto = correct

In this sentence:

• sia giusto
• sia corretto

Both are natural.
Giusto often feels a little more everyday and general.
Corretto can sound slightly more formal or precise.

So the original sentence is perfectly normal, but you may also hear:

controllo che il CAP del destinatario sia corretto

Italian often uses the present tense to talk about future actions when the timing is clear from the context.

Here:

• Prima che la raccomandata parta = before the registered letter goes out / is sent
• controllo = I check

Even though the departure is in the future relative to the checking, the present subjunctive is the normal form after prima che.

This is very common in Italian. English also sometimes does something similar:

• Before it leaves, I check...

So the tense choice is normal and idiomatic.

Yes. Italian word order is fairly flexible, especially with subordinate clauses.

The original sentence:

Prima che la raccomandata parta, controllo che il CAP del destinatario sia giusto.

You could also say:

Controllo che il CAP del destinatario sia giusto prima che la raccomandata parta.

Both are correct. The difference is mainly one of emphasis:

• starting with Prima che... emphasizes the time sequence
• starting with Controllo... emphasizes the action of checking

With the subordinate clause placed first, the comma is very natural and usually expected:

Prima che la raccomandata parta, controllo che...

If the subordinate clause comes after the main clause, the comma is often omitted:

Controllo che il CAP del destinatario sia giusto prima che la raccomandata parta.

So the punctuation follows the structure quite closely.

The original sentence is already natural, but in everyday speech people might simplify parts of it depending on context.

Possible variants:

• Prima di spedire la raccomandata, controllo che il CAP del destinatario sia giusto.
• Prima che parta la raccomandata, controllo che il CAP sia giusto.

Notes:

• prima di + infinitive is possible when the subject is the same
• spedire la raccomandata may feel more concrete than la raccomandata parta
• il CAP alone is enough if the recipient is obvious from context

So the original is correct, but there are several natural alternatives depending on style and context.