The Czech data box: why unread official mail still counts as delivered

The Czech state has a preferred way to send you an official letter, and it is not the post. It is the data box, a secure electronic mailbox that gives a message the same legal force as registered mail. For a foreigner, the surprise comes when a court, a tax office or a city authority writes to a data box that the recipient never opened.

The rule that causes the damage is not about security. It is about time, and it is covered below under deemed delivery.

What it is

A data box (datová schránka) is an electronic mailbox maintained by the state for official communication. Messages in it are authenticated, and the sender and the time are recorded. You use it to receive documents from authorities and to send filings to them, and you can message other box holders, companies included.

The box has an identifier. It is not an email address. You log in to the web interface or the mobile app with a login method the system accepts.

Who has one

Legal persons, such as companies, have a data box by law. The state creates it for them, and the statutory body has to manage it. Since 1 January 2023 the state also sets up a box automatically for sole traders and other self-employed people entered in a public register, such as the trade register (Act No. 300/2008 Coll., as amended by Act No. 261/2021 Coll.), and sends the login details by post. If you are a sole trader, assume you have one. Private individuals who are not in business can request one, and a box can also be set up for you automatically the first time you log in to certain state online services with an electronic identity, unless you have opted out. The service is free.

For individuals the box is voluntary. For foreigners it can be a convenience or, in some situations, a necessity. People who deal with the tax office, apply for benefits or appear before courts often prefer a box, since filings made through it count as electronic submissions. The Financial Administration accepts returns through data boxes; see how to file a Czech personal tax return.

A box also changes how authorities reach you. Someone who has one can expect to be written to there, and an authority may prefer it to paper post. That is convenient while you are paying attention and costly when you are not.

Deemed delivery

This is the rule to understand. When an authority sends a message to your data box, it counts as delivered the moment you, or anyone with access to the box, log in, even if you do not open that particular message. If nobody logs in, it is deemed delivered on the tenth day after it reached the box (Act No. 300/2008 Coll., § 17; as of 2026; check the official source). From that moment the deadlines in the message run, whether you have read it or not.

The consequence is simple: if you have a box, you have to log in. A box left unchecked for three months is a source of missed deadlines, penalties and, in the worst cases, lost appeals. Set up notifications to your email or phone, and check the box on a regular schedule.

How to activate one

There are two main routes.

Online. If you have an electronic identity the state accepts, such as a Czech bank identity, a government-issued digital identity or that of a registered user, you can request a box through the data box information portal. Most bank identities work; see how to open a Czech bank account as a foreigner. Once you submit the request, the box is created and you receive login details.

In person. At a Czech POINT contact point, found at many post offices and municipal offices, a clerk can request the box for you. Bring identity documents such as your passport or residence card. The clerk will give you your first login credentials and explain how to use them.

Foreigners with a residence status can request a box in the same way as Czech citizens. If you need one to deal with a particular authority, ask which method it accepts.

Using it

Once the box is active, log in through the web portal or the mobile app and set up notifications. Learn to read the sender, subject and date. Messages from authorities carry a deadline in the text. Save important messages and their delivery receipts somewhere you can find them.

You can send messages to authorities, for example to file a tax return or send a document to the foreign police or the Labour Office. Sending through the box gives you an official delivery receipt. Not every authority accepts every kind of filing by data box, so check its instructions.

A sensible routine is to open the box weekly, and daily when you are waiting for a decision, such as a residence application or a tax assessment. Put it in the calendar next to the dates that matter.

Companies, sole traders and authorities

If you register a company, the data box is created by law and managed by its statutory body. If you later close the company or hand it over, the box has to be passed on or closed with it. Sole traders, as noted, have one set up automatically. Authorities use the box for formal decisions, requests to supplement documents, tax assessments and court papers, so the people who run a business should treat it as a standing duty and not a one-off setup. Delegating access to an accountant is possible, and some businesses do it, but the person who owns the box remains responsible for the deadlines that start running, so choose a person you trust and agree how often they check.

When you leave

If you leave Czechia, cancel the data box or authorise someone to manage it. An unattended box keeps receiving messages, and the deemed-delivery rule keeps applying. You can ask for the box to be closed at Czech POINT or through the portal, subject to any obligations that remain.

Security

Treat the login as you would online banking. Use a strong password, switch on two-factor authentication if it is offered, and ignore emails claiming to come from the data box system and asking for your login. The official system does not ask for credentials by email.

Common mistakes

• Requesting a box for one filing and never opening it again.
• Setting up notifications to an email address you do not read.
• Assuming that a message you have not opened has not been delivered.
• Leaving the country without closing the box or authorising someone to manage it.
• Forgetting that a sole trader may already have a box created for them.

A worked example

Take a hypothetical freelancer who requests a box in March to file her tax return through it. In July the tax office sends a request for additional documents, with a deadline in the text. She is travelling, her notification email goes to an inbox she has stopped reading, and she does not log in. Ten days after the message was sent it is treated as delivered, and the deadline begins to run from that day. When she opens the box in September, the deadline has passed. The mistake was not in the filing but in the habit of checking.

The same sequence is avoidable with three small steps: notifications to a live address, a weekly look at the box, and an agreement with an accountant or a trusted person to check it during long absences.

Frequently asked questions

Do I need a data box as an employee?

Not necessarily. For individuals who are not in business the box is voluntary, though logging in to some state services with an electronic identity can set one up unless you opt out. Many employees never need one, though people who deal often with the tax office, benefits or courts may prefer it.

What happens if I never open a message?

If you log in, it counts as delivered that day even unopened. If nobody logs in, it is treated as delivered after 10 days. Either way the deadlines in it start to run whether you have read it or not (as of 2026; check the official source).

How do I get a box?

Online with an electronic identity the state accepts, such as a Czech bank identity, or in person at a Czech POINT contact point with your passport or residence card.

Can I close it when I leave Czechia?

Yes. Ask for it to be closed at Czech POINT or through the portal, or authorise someone to manage it. An unattended box keeps receiving messages.

Decide this week whether you need a box. If you work for yourself or deal with the tax office, the answer is almost certainly yes.

This is a general explainer, not legal or tax advice. Rules on data boxes change; check the Ministry of the Interior or a licensed adviser.