Operational guide

How the Mossos guest registry works in practice

This page is the operational playbook: from registering your property in the Mossos system, through capturing guest data and getting it signed, to filing it on time and archiving it for three years. It is written for an owner who is not living in Catalonia and who will, in most cases, delegate the day-to-day execution to a property manager, a cleaning company or a specialist service. The point is to understand exactly what has to happen so you can hold whoever you delegate to accountable for getting it right.

Step 1 — Register the property with the Mossos system

Before any guest data can be filed, the establishment itself must be enrolled in the Mossos guest-registry system. The Generalitat assigns each property a unique identifier that travels in every subsequent submission. Enrolment requires identification by a Spanish Digital Certificate, Cl@ve credentials, or the Catalan idCAT certificate, and is done through the portal at registreviatgers.mossos.gencat.cat.

What goes into the enrolment record:

• Identifying details for the owner or operator — name, NIF or NIE, address.
• Details for the property itself — address, type of accommodation, number of rooms or bedrooms, and the HUT or HUTB licence number where applicable.
• The operational status of the owner — professional or non-professional.
• The contact details for the person who will receive notifications from the Mossos.

For a foreign owner without Spanish credentials, this step in particular cannot be done by you directly. The standard solution is to have the enrolment carried out by your authorised representative using their own certificate, with the appropriate written authorisation in place. If you have several properties in Catalonia each must be enrolled separately and each receives its own identifier; they are not bundled under a single owner identity.

Step 2 — Collect the guest data

Every stay generates a separate submission. For each guest who will spend at least one night on the property — including children — you (or your delegate) must collect a defined set of data points. These fall into two groups: data about the booking (collected once per stay), and data about each individual guest (collected once per person).

Booking-level data

• Booking reference — your internal reference for the stay, or the platform's reference if booked via Airbnb, Booking.com etc.
• Date the booking was made, in the format YYYY-MM-DD.
• Check-in date and time, in the format YYYY-MM-DDThh:mm:ss. This is the actual check-in time, not the time the booking was confirmed.
• Check-out date and time, in the same format.
• Number of guests on the stay and number of rooms occupied.
• Type of payment — categories are cash, card, bank transfer, platform, or other. The actual card or bank-account number is not collected; an earlier draft of the regulation included it, but it was removed before the final version.

Per-guest data — roughly seventeen fields

For each guest individually:

The two fields that catch first-time filers most often: the second surname (Spanish nationals will have one even if they don't immediately offer it — it must be captured) and the document support number for Spanish ID cards (printed on the card, separate from the document number itself). For a US, UK, Australian or other non-Spanish guest, the document type is "passport", there is no support number, and the second surname is left blank.

Step 3 — Get the guest's signature

Every guest aged 14 or over must sign the parte. The signature is what evidences that the guest was identified and that the data on the record matches the document presented. Three forms are acceptable:

• Simple electronic signature — captured on a tablet or phone screen at check-in, linked to the data record.
• Reinforced electronic signature via a pre-arrival check-in flow that sends the guest an email or SMS link, captures the data, validates by OTP, and timestamps the signature. This is by far the most reliable approach for an absentee operation, because it removes the dependency on a physical encounter at the door.
• Wet signature on paper — still a valid evidence of identification, retained by the owner as part of the file. Note that paper is no longer the medium of submission; the data goes electronically to the Mossos regardless.

The signed record stays with the owner (or the representative acting for the owner) as part of the three-year archive. The signature is not uploaded to the Mossos portal; what is uploaded are the data fields. If the Mossos later requests evidence of identification, you produce the signed record from your archive.

Step 4 — Submit to Mossos within 24 hours

The deadline is 24 hours from actual check-in. This is the rule that creates most of the operational friction: late-night arrivals, weekend check-ins, public holidays, owners on holiday themselves and out of phone contact, internet outages in rural properties. The standard way to handle the friction is to push the data capture earlier than check-in — typically two to seven days before arrival — using a pre-arrival check-in flow that emails or messages the guest, lets them complete the data and sign at their own pace, and produces a record ready to file the moment they actually arrive.

The Mossos portal currently accepts submissions in two ways:

1. Manual entry through the web form — practical for very low volumes, exhausting for anything beyond a handful of stays a month, and the path on which errors are most common.
2. Structured file upload — a defined format (typically XML or a CSV-style schema published by the Generalitat) that allows a single file to carry multiple guest records. This is the path that specialist services and modern property-management software target.

Unlike the national SES platform, the Mossos system does not currently expose a public REST API for direct integration. This is widely expected to change, and the Generalitat has signalled it is working on an API, but as of mid-2026 the practical reality is that submission happens by file upload through the portal's authenticated session. After a successful submission the system returns a confirmation receipt; this is the document you keep as evidence of having filed in time.

Step 5 — Keep the records for three years

Professional hosts must keep the file — the guest data submitted, the signature record, and the Mossos receipt — for three years from the end of each stay. The retention must be in a form that lets the Mossos consult the records on request, which in practice means a structured electronic archive organised by stay rather than a folder of loose PDFs. The data must be deleted at the end of the three-year period; you cannot keep it indefinitely on the assumption that more data is always better.

Non-professional hosts are not formally obliged to maintain the documentary archive but are well advised to do so anyway: it is the only document you can produce if the Mossos later asks you to substantiate a filing, and it costs nothing meaningful to keep.

Delegating to a representative while remaining responsible

For an owner abroad, the practical execution of every step above will normally happen through someone else — your property manager, your cleaner-co-host arrangement, a specialist compliance service, or a Catalan gestoría. Three things are worth being clear about.

You remain the legally responsible party

The obligation rests on the host. Delegating the filing does not transfer the obligation. If your property manager forgets to file on a stay, the sanction is addressed to you, not to the manager. The contract between you and your manager is what governs whether the manager indemnifies you, but the public-law liability stays with you. This is identical in structure to how tax filings work: you can pay an accountant to file your return, and you are still responsible if the return is wrong.

The authorisation must be in proper form

The representative needs to be formally authorised to act before the Generalitat on your behalf. This typically means a written power of attorney that authorises the representative to file guest data, accept notifications, and represent you in any related proceedings. In many cases the authorisation is registered in the registre electrònic d'apoderaments of the Generalitat or in the Spanish state registry, which lets the Mossos portal recognise the representative's certificate as standing in for yours. A handshake agreement is not enough; the portal will not accept submissions filed by a certificate it cannot link to your establishment record.

Build a feedback loop

The most common failure mode for delegated compliance is silence: you assume the manager is filing because you would notice if they weren't, but you would not. Build in a periodic check — monthly or quarterly — that confirms a Mossos receipt exists for each stay you know happened. A good specialist service will produce this report automatically; for an informal arrangement, ask for it explicitly.

Practical patterns that work for absentee owners

Pre-arrival check-in by message

Once the booking is confirmed (via Airbnb, Booking or direct), an automated message goes out to the lead guest with a link to a check-in form. The form collects the data for all guests, accepts the lead guest's signature on behalf of any minors, captures secondary guests' signatures via OTP if they have separate emails or phones, and produces a stay record that is ready to file. This pattern moves the friction from the doorstep, where you aren't, to the days before arrival, when the guest has time to deal with it.

Filing at check-in, not at end-of-day

Many manual filers wait until evening, when they have time to "do the admin", to upload the day's stays. This works until it doesn't — until one stay is missed, falls into the next day, and breaches the 24-hour rule. The safer pattern is to file at the moment of check-in: the data is already collected from the pre-arrival flow, so the filing step is effectively automatic. Anything that uses a queue with a defined cutoff each day, rather than a real-time submission, is taking on avoidable risk.

One archive across all your properties

If you own more than one property in Catalonia, or properties both in Catalonia and elsewhere in Spain, keep the three-year archives in a single organised location, ideally with a per-property and per-stay folder structure. The point is consultability: if a Mossos inspection asks for the records of stays in March 2025, you should be able to produce them in minutes, not hours.

Things that look like compliance but aren't

• Airbnb's or Booking's own communication to authorities. Platforms do report bookings and cancellations to the relevant authority, but this is a parallel obligation on the platform. It does not satisfy the owner's obligation to file the actual check-in.
• A passport photocopy in your records. Photocopying or scanning the document is, separately, a GDPR breach. You record the data fields; you do not store the image of the document.
• "My manager keeps a spreadsheet." A spreadsheet of guests is not a filing to the Mossos. The data has to actually be submitted to the portal within 24 hours of each check-in.
• Filing once a month in a batch. The 24-hour rule is per-stay, not per-month. Batching outside the window is non-compliance.
• A registration on SES.Hospedajes. If your property is in Catalonia, an SES registration covers the wrong system. The data needs to be in Mossos, not in SES.

For an owner abroad, the goal is not to do this work yourself; the goal is to be sure it gets done. The five steps above are the test you apply to whoever is doing it on your behalf.