What the status means
- Required by law
- The law prescribes registered mail, sometimes as one of a short list of accepted methods. Another channel can make the letter invalid.
- Recommended
- No form is prescribed, but a deadline or the need to prove receipt makes registered mail the usual safe choice.
- Often required by contract
- The law sets no form. Contract terms often ask for registered mail, so check yours.
- Not needed
- Email, an online form or a cancellation button is valid and common. Registered mail adds little.
All letters at a glance
| Letter | Status |
|---|---|
| Tenant notice to leave a rented home | Recommended |
| Landlord notice of non-renewal | Recommended |
| Reply to a rent increase | Recommended |
| Reclaiming the rental deposit | RecommendedLocal differences |
| Notice of repairs to the landlord | Recommended |
| Demand to a tenant for unpaid rent | Recommended |
| Resignation letter | Recommended |
| Dismissal letter from the employer | Recommended |
| Cancelling an insurance policy at renewal | Recommended |
| Cancelling phone or internet service | Not needed |
| Cancelling a gym membership or subscription | Not needed |
| Switching or ending an electricity or gas contract | Not needed |
| Formal demand for payment | Recommended |
| Letter disputing a debt | Recommended |
| Appeal against a tax assessment | Not neededLocal differences |
| Appeal against a traffic fine | Not neededLocal differences |
| Withdrawing from an online or distance purchase | Not needed |
| Warranty claim for a faulty product | Not needed |
Housing and rent
Tenant notice to leave a rented home
The law sets no form, but the notice must arrive in time and you are the one who must prove it. A carta certificada proves delivery and the date; a burofax with certified content also proves the text.
- Deadline
- At least 30 days before the end of the contract or yearly extension during the first five years (seven if the landlord is a company), two months after that; to leave early, after six months and with 30 days' notice.
- Other valid ways
- Any written notice the landlord signs as received, or an email the landlord answers, is also valid.
- Sources
- BOE, Ley 29/1994 de Arrendamientos Urbanos (texto consolidado)Correos, Burofax premium para particularesLegal basis: arts. 9.1, 10.1 y 11 Ley 29/1994 (LAU)
Landlord notice of non-renewal
A landlord can only end the lease with timely notice, and if the date and content cannot be proven the lease renews automatically. That is why a burofax with certified content or a notary is used, rather than a plain carta certificada.
- Deadline
- Four months before the end date once five years have passed (seven for a company); two months to recover the home for an agreed need. For end dates after 15 November 2026, six months (Royal Decree-law 28/2026, awaiting ratification), except leases ending before 15 May 2027.
- Other valid ways
- A notarial notice, or hand delivery with the tenant's signed receipt.
- Sources
- BOE, Ley 29/1994 de Arrendamientos Urbanos (texto consolidado)BOE, Real Decreto-ley 28/2026 sobre estabilidad de los contratos de arrendamiento de viviendaLegal basis: arts. 9.3 y 10.1 Ley 29/1994 (LAU); Real Decreto-ley 28/2026
Reply to a rent increase
An increase can only be charged if the contract allows it, it is notified in writing and stays within the official index; you may ask for the index certificate. If you disagree, put it in writing with proof of receipt, for example by burofax.
- Deadline
- The new rent is due from the month after the written notice, so reply promptly.
- Other valid ways
- An email or written message you keep, if the landlord replies to it.
- Sources
- BOE, Ley 29/1994 de Arrendamientos Urbanos (texto consolidado)Legal basis: art. 18 Ley 29/1994 (LAU)
Reclaiming the rental deposit
By region: In many regions the landlord must lodge the deposit with a regional body, but you still claim the refund from the landlord.
If the landlord does not return the deposit, the law requires you to try to negotiate before suing and to prove the other side received your proposal and its content. A burofax with certified content is the usual way to show this.
- Deadline
- Once a month has passed since you returned the keys, the unpaid deposit earns interest; after asking to negotiate, if there is no answer within 30 days you may go to court.
- Other valid ways
- An email or message the landlord answers, although proof of receipt and content helps if you go to court.
- Sources
- BOE, Ley 29/1994 de Arrendamientos Urbanos (texto consolidado)BOE, Ley Orgánica 1/2025 de eficiencia del Servicio Público de JusticiaServicio Público de Justicia, Cuándo es obligatorio acudir a un MASCLegal basis: art. 36.4 Ley 29/1994 (LAU); arts. 5, 7 y 10 LO 1/2025
Notice of repairs to the landlord
Tenants must report needed repairs promptly, and an October 2026 reform lets them demand repairs in writing with a quote and act if there is no answer. For that period to run you need to prove the date of receipt, so a burofax is commonly used.
- Deadline
- As soon as possible; under the reform, the landlord has 15 calendar days from receipt of the written request.
- Other valid ways
- An email or message with photos, if the landlord replies.
- Sources
- BOE, Ley 29/1994 de Arrendamientos Urbanos (texto consolidado)Legal basis: art. 21.3 y 21.5 Ley 29/1994 (LAU), apartado 5 añadido por Real Decreto-ley 29/2026
Demand to a tenant for unpaid rent
If the landlord demands payment in a provable way at least 30 days before suing, the tenant can no longer stop the eviction by paying during the case. A burofax with certified content or a notary is used for this; a carta certificada does not prove content. The same letter can also serve as the prior negotiation attempt the law requires before suing.
- Deadline
- At least 30 days before filing the claim.
- Other valid ways
- A notarial demand or any other reliable method that proves delivery and content.
- Sources
- BOE, Ley 1/2000 de Enjuiciamiento Civil (texto consolidado)BOE, Ley Orgánica 1/2025 de eficiencia del Servicio Público de JusticiaCorreos, Burofax premium para particularesLegal basis: art. 22.4 Ley 1/2000 (LEC); arts. 5 y 10 LO 1/2025
Work
Resignation letter
The law sets no form, but you must give the notice set by the collective agreement or local custom, or the employer may deduct pay. The usual way is to hand in two copies and ask for one to be signed; if they refuse, a burofax with certified content.
- Deadline
- The notice period in the collective agreement, often 15 days.
- Other valid ways
- Hand delivery with a copy the employer signs as received; a burofax if the employer will not sign.
- Sources
- BOE, Estatuto de los Trabajadores (texto consolidado)Legal basis: art. 49.1.d Estatuto de los Trabajadores
Dismissal letter from the employer
A dismissal must be in writing with the reasons and effective date, but the law does not set how to deliver it. When it cannot be handed over, a burofax with certified content is the usual proof of delivery and text.
- Deadline
- For dismissal on objective grounds, 15 days' notice; the employee has 20 working days to challenge it.
- Other valid ways
- Hand delivery with a signed receipt, or before witnesses if the employee refuses to sign; a burofax if the employee is absent.
- Sources
- BOE, Estatuto de los Trabajadores (texto consolidado)Legal basis: arts. 53.1 y 55.1 Estatuto de los Trabajadores
Insurance and subscriptions
Cancelling an insurance policy at renewal
The law requires written notice one month ahead, and if the insurer says it arrived late the policy renews. A method that proves receipt and content, such as a burofax, is therefore advised, especially if the policy offers no online cancellation.
- Deadline
- At least one month before the policy year ends (the insurer needs two months).
- Other valid ways
- Many insurers accept email or the customer portal; keep the receipt showing the date.
- Sources
- BOE, Ley 50/1980 de Contrato de Seguro (texto consolidado)Legal basis: art. 22 Ley 50/1980 de Contrato de Seguro
Cancelling phone or internet service
The operator must accept cancellation through the channel you signed up with and give you proof of the request with a reference number. A letter only makes sense if the operator fails to give that proof.
- Deadline
- At least two working days before the date you want the service to end; check for any minimum-term commitment.
- Other valid ways
- By phone, online or through the same channel you signed up with; ask for the cancellation reference number.
- Sources
- BOE, Real Decreto 899/2009, carta de derechos del usuario de comunicaciones electrónicasBOE, Ley 10/2025 de servicios de atención a la clientelaLegal basis: arts. 7 y 26.2 Real Decreto 899/2009; Ley 10/2025
Cancelling a gym membership or subscription
The law lets you cancel the same way you signed up and bans disproportionate hurdles. If the terms ask for advance notice and the business gives no confirmation, a burofax records the date and content.
- Deadline
- Any notice period in the terms, if reasonable.
- Other valid ways
- Through the same channel you joined (website, app, front desk); keep the confirmation.
- Sources
- BOE, Ley General para la Defensa de los Consumidores y Usuarios (texto consolidado)Legal basis: art. 62.3 y 62.4 TRLGDCU (Real Decreto Legislativo 1/2007)
Switching or ending an electricity or gas contract
You do not need to write to the old supplier: the old contract ends when the new supplier makes the switch. Energy companies must handle cancellations and complaints by phone, post and an electronic channel, and give you a tracking code.
- Other valid ways
- When you switch, the new supplier handles ending the old contract; for other requests, phone or the customer portal.
- Sources
- CNMC, Comercialización y suministro eléctricoBOE, Ley 10/2025 de servicios de atención a la clientelaLegal basis: Ley 10/2025, art. 2.1.a; TRLGDCU art. 62.3
Money and debts
Formal demand for payment
A demand out of court puts the debtor in default, and before going to court the law requires a negotiation attempt with proof that the debtor received the proposal and could see its full content. A burofax with certified content is the usual proof; a carta certificada does not prove the text.
- Deadline
- If there is no reply within 30 calendar days of receipt, the negotiation counts as failed and you may sue; the request also stops the limitation period running.
- Other valid ways
- A notarial demand, or a document signed by both parties; an email works if you can prove it was received and readable.
- Sources
- BOE, Ley Orgánica 1/2025 de eficiencia del Servicio Público de JusticiaServicio Público de Justicia, Cuándo es obligatorio acudir a un MASCCorreos, Burofax premium para particularesLegal basis: art. 1100 Código Civil; arts. 5, 7 y 10 LO 1/2025
Letter disputing a debt
There is no required form, but recording that you dispute the debt protects you if it ends up in court, where the law requires a documented prior attempt to negotiate. A burofax with certified content or a complaint with a reference number works as proof.
- Other valid ways
- A complaint to the company's customer service with a reference number, if offered.
- Sources
- BOE, Ley Orgánica 1/2025 de eficiencia del Servicio Público de JusticiaServicio Público de Justicia, Otros MASCBOE, Ley Orgánica 3/2018 de Protección de Datos (texto consolidado)Legal basis: arts. 5 y 10 LO 1/2025; art. 20 LO 3/2018
Tax and fines
Appeal against a tax assessment
By region: Regional and local taxes are appealed to the region or town hall; the Basque Country and Navarre have their own tax authorities.
The appeal is normally filed online or at a public registry, which gives a dated receipt. If you post it, use correo administrativo at a post office, with the envelope left open so the document is stamped, so the posting date counts.
- Deadline
- One month from the day after notification.
- Other valid ways
- The tax agency's online office, any public registry, or a post office using correo administrativo.
- Sources
- Agencia Tributaria, Recurso de reposiciónBOE, Ley 39/2015 del Procedimiento Administrativo Común (texto consolidado)Legal basis: arts. 223 y 235 Ley 58/2003 General Tributaria; art. 16.4 Ley 39/2015
Appeal against a traffic fine
By region: Municipal fines are appealed to the town hall; Catalonia and the Basque Country have their own traffic authorities.
Appeals are filed online or at a registry, which gives a dated receipt. If you use the post, sending it as correo administrativo makes the date you handed it in count.
- Deadline
- 20 calendar days from notification; appealing means losing the early payment discount.
- Other valid ways
- The traffic authority's online office or app, a public registry, or a post office using correo administrativo.
- Sources
- Sede electrónica DGT, Presentación de alegación o recurso a una multaBOE, Ley sobre Tráfico y Seguridad Vial (texto consolidado)Legal basis: art. 95 Real Decreto Legislativo 6/2015 (Ley de Tráfico); art. 16.4 Ley 39/2015
Consumer purchases
Withdrawing from an online or distance purchase
Any clear statement is valid, and the date you send it is what counts. Since you must be able to prove it, keep the email or the acknowledgement the seller has to send you.
- Deadline
- 14 calendar days from receiving the goods or signing a service contract.
- Other valid ways
- Email, the seller's online form or the official model withdrawal form.
- Sources
- BOE, Ley General para la Defensa de los Consumidores y Usuarios (texto consolidado)Centro Europeo del Consumidor en España, Consumer rightsLegal basis: arts. 71, 104 y 106 TRLGDCU (Real Decreto Legislativo 1/2007)
Warranty claim for a faulty product
The law sets no form: telling the seller about the defect is enough, and the seller must give you a written record. If there is no answer and you plan to go to court, a prior complaint with proof of receipt, such as a burofax, also counts as the negotiation attempt the law requires.
- Deadline
- Three years from delivery for new goods (at least one year for second-hand goods).
- Other valid ways
- At the shop, through its customer service, or with the official complaint form; a burofax if the seller does not respond.
- Sources
- BOE, Ley General para la Defensa de los Consumidores y Usuarios (texto consolidado)Centro Europeo del Consumidor en España, GuaranteesServicio Público de Justicia, Otros MASCLegal basis: arts. 120, 121 y 123 TRLGDCU; art. 5 LO 1/2025
FAQ
Which letters must go by registered mail by law in Spain?
None of the letters listed here. The law does not make carta certificada the required form for common notices, claims or cancellations. What it often asks is that you can prove the other side received the letter in time, and sometimes what it said.
Carta certificada or burofax?
A carta certificada proves sending and delivery. A burofax with certified content also proves the text. For a landlord's notice, a payment demand or a deposit claim people usually choose the burofax, because before going to court the law asks for a negotiation attempt with proof that the other side could see the proposal.
How do I appeal a fine or a tax assessment in Spain?
Online or at a public registry, which gives a dated receipt. If you use the post, send it as correo administrativo with the envelope open so the document is stamped: the date you hand it in then counts.
Do I need a letter to cancel a phone contract or a gym in Spain?
No. The operator must accept cancellation through the channel you signed up with and give you a reference number; a gym must also let you cancel the way you joined. A burofax only makes sense if you get no such confirmation.
Sources and review
Each letter links to the official source it is based on: legislation, a government portal or a public authority. Practice and court rulings can change; check the source before you rely on a deadline. Sources checked on 28 October 2026.
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