A guest from Berlin arrives on Friday and leaves on Sunday. By when do you have to report them to the cizinecká policie (Foreign Police)? By Wednesday. The deadline is 3 working days after check-in, the day of arrival doesn't count, and weekends and public holidays extend it. Everyone who isn't a Czech citizen has to be reported — so that includes a guest from Slovakia, and children too.

That's the law. Here's what it looks like when you do it a few hundred times a year.

Registration takes time, reporting then takes minutes

The police first have to register you in UbyPort (the Foreign Police reporting system). The form “Žádost o registraci nového ubytovacího zařízení” (application to register a new accommodation facility) generates a PDF, which you send via datová schránka (data box, the Czech official e-mail system) to the Directorate of the Foreign Police Service, and then you wait. Officially up to 30 days; in practice it's often faster, but don't count on it. You'll receive an IDUB (facility identifier), a short code and login details.

One tip that saves you a second round: in the application, tick right away that you also want access to the web service. A regular login to the web form is enough for manual reporting; any system that's supposed to report on your behalf needs a separate web service account. Anyone who doesn't ask for it straight away has to apply again and wait again.

What gets reported and where mistakes happen

First name, surname, date of birth, citizenship, address abroad, document number, visa number, purpose and length of stay. It sounds simple, but UbyPort has strict formats and three places where things regularly get stuck:

• Address abroad. A mandatory field that gets forgotten most often. UbyPort wants the street, city and country, not just “Germany”.
• Characters in the name. The field accepts basic Latin letters and Central European diacritics. Ø, ñ, ã or anything in Cyrillic gets silently dropped — “Søren” becomes “SREN”. The solution is to copy the name from the machine-readable zone at the bottom of the passport, where it's already converted.
• The visa field. It isn't just the visa number. For a guest with a biometric passport you write BIOMETRIKA, for a guest with an EU residence card the word POBYT. If you leave it empty, the report still goes through, but not the way the police methodology wants it.

Doručenka: the document you actually have to read

After you submit, UbyPort offers a PDF called Doručenka (delivery receipt). Most people close it. That's a mistake. The delivery receipt tells you how many records were accepted, how many were rejected and why. A rejected guest hasn't been reported, and their deadline keeps running.

And now the part I had to check in the UbyPort error list, because it scared me at first: the delivery receipt sometimes shows the message “Oznámeno pozdě” (Reported late). It looks like a rejection. It isn't a rejection. The record has been accepted; the police have simply noted that it came in after the deadline. So the report is valid, you just sent it late — which is still better than not sending it at all.

What happens if you miss it

The fine is up to CZK 50,000 per offense — not for each guest separately, but for failing to meet the obligation. The same upper limit applies to a missing or badly kept domovní kniha (house book), which is a second, separate obligation. The police check it during on-site residence inspections, and you have to produce the house book with the foreigners currently staying there immediately, not the next day.

From experience: send a late report anyway. The system accepts it and just flags it. Never skip a report on the grounds that “it's too late anyway”.

The guest extended, the guest left early

You always report the stay as it's known at that moment. If the guest stays longer, you send a new report with the new dates. If they leave early, you don't report anything; you just record the actual end in the house book.

How I have it set up today

The guest fills in their details in advance on their phone via a link, the app checks the allowed characters and the document format, picks the right purpose-of-stay code and sends the report within the deadline. When UbyPort rejects something, I see it immediately as an error on the booking, not in a PDF I'd have to open. That's hundreds of reports a season I don't have to think about — and the only thing done manually is that one application for the web service.