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Registering or updating an Italian business with the Single Communication (ComUnica)

Anyone starting a business, or changing its details, who registers with the Companies Register (Registro delle Imprese) or the REA uses the Single Business Communication (ComUnica): a single online filing, compulsory since 1 April 2010, sent to the Companies Register through registroimprese.it, which passes its content on to the Agenzia delle Entrate (VAT number), INPS, INAIL, the Register of craft businesses and, where needed, the SUAP. You need a digital signature, a PEC mailbox and access to the Telemaco service. The ComUnica receipt entitles you to start trading immediately, provided the other legal requirements are met.

Up to date for 2026 — verified on September 25, 2026Official procedure, no printed formGuide: about 60 min

This content is part of the path: Starting a business under the flat-rate regime· Step 9 of 12· Next step: Starting a business activity in Italy with a SCIA filed with the SUAP (Impresa in un giorno)

Deadlines

Before trading starts
For a sole trader the start date cannot precede the filing of ComUnica
Within 30 days of the SCIA
Filing ComUnica with the Companies Register if the SCIA was filed separately with the SUAP
By 7 pm
Automatic registration the same day; after that, on Saturdays or public holidays, the next working day

Documents to prepare

  • A valid digital signature device
  • An active PEC mailbox, which will be the business's digital address
  • Telemaco credentials (SPID, CNS or CIE) and a prepaid fund for filing fees and stamp duty
  • Details of the business, the activity and the people involved for the Companies Register, Agenzia delle Entrate, INPS and INAIL forms
  • Any SCIA for the SUAP, and a special power of attorney if a professional files for you
See the procedure on the official site

No form is attached to this procedure: the link leads to the official page that describes it.

What this page gives you

The guide above and the link to the official site. ActioFin does not produce any document for this page: whatever you fill in or file is done on the official medium.

Who this applies to

  • Sole traders and companies required to register with the Companies Register or the REA, at start-up and at every later change
  • Even when the only obligation is the VAT declaration: since 1 April 2010 anyone required to register must go through the Single Communication, completing the AA7/10 or AA9 form within it
  • Craft businesses, for registration with the Register of craft businesses
  • Anyone starting an activity subject to SCIA, which can be filed together with ComUnica at the Companies Register
  • Not professionals with no registration obligation, who open a VAT number with form AA9/12; for closing the business see the VAT number closure guide

Worked example

Luca Rinaldi, plumber in Rimini, opens his craft sole-trader business

Luca registers on Telemaco with SPID, tops up the prepaid fund used to pay filing fees and stamp duty, and fills in ComUnica with the DIRE application: registration with the Companies Register and the Register of craft businesses, the Agenzia delle Entrate form for the VAT number, INPS craft-worker registration and an INAIL position, plus the SCIA for the SUAP filed at the same time. He signs the file digitally and sends it on Tuesday 13 October 2026 at 8:30 pm: it will be registered on Wednesday 14. With the receipt he may start trading from that day; each body will then write to the PEC address given about the outcome of its own part.

How to fill it in, step by step

  1. Get a valid digital signature and an active PEC mailbox, which becomes the business's digital address for communications from the bodies involved.
  2. Register with the Telemaco service (SPID, CNS or CIE) and set up the prepaid fund for filing fees and stamp duty, where due.
  3. Fill in the file with a chamber-of-commerce tool: DIRE, or Pratica semplice to register a sole trader or report the PEC address.
  4. Enter the applicant's details and the purpose of the communication in the summary form, and add the forms for each body: Companies Register, Agenzia delle Entrate, INPS, INAIL and any SCIA.
  5. Sign the whole file digitally, yourself or the authorised person, which may be a professional holding a special power of attorney.
  6. Send it to the Companies Register through registroimprese.it and keep the receipt, which entitles you to start trading immediately.
  7. If the file is suspended, regularise it within the stated time using only the file's message log, and close every correction.
  8. For every later change in the business's details, file a new ComUnica the same way.

Good to know

  • A sole trader can register with the Companies Register « without immediate start of trading », that is as inactive.
  • The Companies Register, the Agenzia delle Entrate, INPS and INAIL each process their own part and report the outcome to the business separately.
  • When a suspended file is fully « resent », the Agenzia delle Entrate and INAIL forms cannot be filled in again: they have already been transmitted, and their errors are corrected directly with that body.
  • With a SCIA you can choose: separate filing (SCIA with the SUAP and ComUnica within 30 days) or joint filing, both at the Companies Register.
  • Filing fees and stamp duty are not given here: the amounts depend on the filing and are paid from the Telemaco fund.

Common mistakes

  • Giving a sole trader a start date earlier than the filing of ComUnica.
  • Opening a business's VAT number by sending the Agenzia form AA9/12 alone: anyone required to register must use the Single Communication, which handles registration and VAT number together.
  • Giving a PEC address that is not active: it is where all the bodies' acts and communications arrive.
  • Answering a suspension by phone or email instead of in the file's message log, or forgetting to close the correction.
  • Sending the file in the evening or on a Saturday and expecting same-day registration.

Frequently asked questions

What is the Single Business Communication?

It is the online filing, compulsory since 1 April 2010, through which a business meets in one submission to the Companies Register its registration, tax (VAT number), social security (INPS) and insurance (INAIL) obligations, plus any SCIA.

What do I need to send it?

A valid digital signature, an active PEC mailbox, access to the Telemaco service with a prepaid fund for fees and stamp duty, and a filing tool such as DIRE or Pratica semplice.

When can I start trading?

From the ComUnica receipt, which entitles you to start the business immediately provided the other legal requirements are also met.

Does a company that only needs a VAT number use ComUnica?

Yes, if it is required to register with the Companies Register or the REA: since 1 April 2010 it must use the Single Communication even when the VAT declaration is the only obligation.

Can I hand the filing to a professional?

Yes, by giving them a special power of attorney to file the Single Communication with the Companies Register.

Go further

Compute the related amounts

Understand this form: the related course

Related forms

Official sources

Read in Italian

Guide and document provided for information purposes only; they do not constitute personalised legal or tax advice. Check the recipient organisation's requirements and consult a professional if needed.