Terminating a mobile or internet contract in Switzerland: keeping minimum terms and deadlines in view

Anyone in Switzerland who wants to terminate their mobile contract, home internet or a combined telecom subscription regularly trips over rigid contract structures, automatic renewal clauses and opaque deadlines. Unlike Germany or countries in the European Union, where the legislator has imposed very short monthly notice periods once the minimum contract term has expired, the Swiss telecommunications sector operates in a regulatory and contractual environment of its own.

A smooth change of provider depends on knowing the exact deadlines, distinguishing the phases of the contract and making no costly mistakes when porting your number.

This comprehensive expert guide sets out in detail what happens after the minimum contract term expires, how to keep correctly to the notice periods at Swisscom, Sunrise or Salt, and what you absolutely have to watch when porting your number.

1. The two essential phases of a telecommunications contract

Almost every mobile or internet contract in Switzerland is concluded with a fixed commitment period. To manage the termination process without error, two distinct phases have to be told apart:

Phase 1: the initial minimum contract term

• The classic duration: when taking out a subscription — often in combination with subsidised smartphones or installation discounts for the fibre router — customers generally sign up for a minimum term of 12 or 24 months.
• The consequence of leaving early: anyone who wants to dissolve a running contract before this minimum term expires generally has to pay the sum of all outstanding monthly basic charges up to the regular end date as compensation. Leaving early during this period is practically ruled out without a compelling goodwill reason or expensive release fees.

Phase 2: automatic renewal once the minimum term has expired

• What happens after month 12 or 24? As soon as the agreed minimum term is over, the contractual relationship continues automatically for an indefinite period with most providers.
• The applicable notice periods: the general terms and conditions of the large Swiss providers set a standard notice period of 60 days (2 months) to the end of any month once the initial term has passed. The historically rigid termination dates at the end of a quarter have largely been replaced at the major players by more flexible month-ends. A quick look at the current contract terms gives complete certainty here.

2. The differences between the major Swiss providers

Every network operator and internet service provider applies its own administrative rules. An overview of the largest brands shows common practice:

• Swisscom: for the modern mobile and internet offerings, a notice period of 60 days to the end of the month applies once the initial term has expired. The process runs straightforwardly through the digital customer portal (My Swisscom), via chat or in writing.
• Sunrise and UPC: here too a standard period of two months applies after the minimum term. With combined multi-services (internet, television, landline and mobile), the customer centre has to be checked carefully to see whether additional options are cancelled separately or as one package.
• Salt: likewise requires a two-month period on standard tariffs. With Salt, note that terminations have to go through specific channels (telephone support with subsequent written confirmation, or by post) in order to be legally valid.

3. The biggest pitfall: number portability (porting)

Anyone switching provider who wants to keep their existing mobile or landline number goes through the number-porting process. This is where most day-to-day mistakes happen, and they can lead to double invoices or, in the worst case, to losing the number.

The golden rules for a successful port:

• Never terminate the old mobile contract yourself prematurely. If you want to move your mobile subscription to a new provider, do not on any account terminate the existing contract on your own initiative before the porting process has started. If the SIM card is cancelled too soon, the number is deleted from the system and porting it afterwards becomes impossible.
• Instruct the new provider: you conclude the new contract and select the "number portability / porting" option during the order process. The new telecom partner manages all the administrative communication with the previous company in the background and coordinates the exact activation date.
• Allow lead time: porting on the Swiss network usually requires a processing time of 10 to 20 working days. This administrative buffer absolutely has to be factored into the planning.
• Settle remaining obligations: successfully taking your number with you does not legally release you from the costs of an old contract still running. If several months of the minimum term remain, the old provider's monthly charges have to continue to be paid in parallel until the official end of the contract, unless you buy your way out with a goodwill payment.

4. Step by step: terminating and switching telecom contracts safely

• Establish the contract status and deadlines: log into your digital customer account to check whether the initial minimum term has already expired, or when the exact end date will be reached.
• Choose the new provider and start the port: conclude the new contract. With mobile subscriptions, number portability is ordered directly at that point. For pure fibre or internet connections, the date is coordinated so that no days-long outage arises.

Submit the termination:

Internet and landline: submit the termination in writing, keeping to the two-month notice period.

Mobile: where a port is involved, the new provider usually takes care of terminating the old contract automatically as of the porting date. It is nonetheless advisable to check the confirmation letters from both parties.

• Return the hardware on time: do not forget to send rented routers, TV boxes or fibre modems back to the old provider in their original packaging once the contract has ended, to prevent expensive charges for unreturned equipment.

5. Legally sound template: terminating an internet or landline contract

For the termination of a plain internet or landline connection without number porting, the following template text can be used. For evidential reasons the document should be submitted by registered post or through the provider's official digital service channels:

[Your first and last name][Your street and number][Postcode and town][Your customer or contract number]
[Name of the telecom provider, e.g. Swisscom / Sunrise / Salt][Customer service / terminations department][Street and number][Postcode and town]
[Your town], [date, e.g. 15.06.2026]
Subject: termination of the internet and landline contractCustomer number: [enter your customer number here]Contract or connection number: [enter your contract number]
Dear Sir or Madam
I hereby terminate my internet and landline contract named above, in compliance with the contractual notice period, as of the next possible date on [desired end date, e.g. 31 August 2026].
Please send written confirmation of the termination stating the exact end of the contract, together with information on returning any rented equipment, to the address given.
Thank you for handling this cooperatively and promptly.
Yours faithfully
_________________________________________[Your handwritten signature][Your first and last name in block letters]

Conclusion: precise planning makes for a smooth change of provider

Switching telecom provider in Switzerland runs smoothly as long as the underlying mechanics are understood. Anyone who keeps an eye on the minimum terms, sticks strictly to the notice periods and preserves the chronological order when porting a number steers reliably towards better conditions or faster connections, without unexpected costs or interruptions in service.