Finland has introduced mandatory verification requirements for all Sender IDs used for Application-to-Person (A2P) SMS traffic to Finnish mobile subscribers.
Under Finnish Transport and Communications Agency Traficom regulations, Sender IDs must be either authorised through the industry authorisation process or protected (registered) through Traficom's official SMS Sender ID service.
Messages sent using unauthorised Sender IDs may be relabelled as Unknown or blocked by Finnish operators.
The requirements apply to organisations sending SMS messages to Finnish mobile numbers (+358), regardless of where the sender is based.
What is a Sender ID?
A Sender ID is the alphanumeric name or number shown as the sender of an SMS message, such as a brand, company, or service name.
It is the unique identification that appears on the recipient’s mobile device as the sender of the message, enabling recipients to recognise the origin of the message and supporting trust.
Sender ID requirements
Sender IDs used in Finland must meet the following requirements:
All Sender IDs used for business messaging must be authorised before use. This applies to:
alphanumeric Sender IDs
Finnish long numbers
international long numbers
Finnish short codes
international short codes
Alphanumeric Sender IDs can be up to 11 characters long.
Sender IDs aren’t case-sensitive.
For international compatibility, Sender IDs should only contain:
A-Z
a-z
0-9
spaces
Sender IDs can’t begin or end with a space, or contain consecutive spaces.
Sender IDs can’t be authorised if they:
are misleading
could cause confusion about the sender’s identity
are offensive
go against good industry practice
are already protected by another organisation in the Traficom register.
Learn more in Traficom’s list of protected Sender IDs.
What happens if a Sender ID is not authorised?
Finnish operators enforce Traficom’s Know the Sender requirements:
Since 4 May 2026: unauthorised Sender IDs are replaced with Tuntematon (Unknown), and operators can block unauthorised SMS traffic.
From 2 November 2026: messages from unregistered alphanumeric Sender IDs are delivered as Roskaposti (Spam), or blocked. Messages from unregistered numeric Sender IDs are blocked.
Sender ID registration process
There are two parts to registering a Sender ID in Finland: authorisation, which is required, and protection, which is optional.
Authorisation (required)
Authorisation confirms that your organisation has the right to use the Sender ID. Most businesses only need authorisation.
We manage the authorisation process on your behalf to make sure you meet Finnish operator requirements.
Complete our Sender ID registration form, including the Sender IDs you want to use and your organisation’s details.
If we ask for it, provide evidence that you own the brand or are affiliated with it.
We submit the request through the Finnish authorisation framework.
Once approved, the Sender ID is authorised for use on Finnish networks.
Protection (optional)
If you want exclusive rights to an alphanumeric Sender ID in Finland, you can also register it with Traficom. Other organisations can’t use a protected Sender ID. Traficom charges an annual fee for protected Sender IDs.
Protected Sender IDs must:
Match your organisation’s business name, auxiliary business name, or parallel business name in the Finnish Business Information System (YTJ)
Meet Traficom’s technical format requirements
Belong to an organisation that can show it has the right to the name, through its:
legal name
registered trademark
established domain name
a clearly recognisable abbreviation or derivative of any of these
To protect a Sender ID:
Apply through Traficom’s Sender ID application service.
Show that the Sender ID matches your registered organisation name.
Traficom reviews the request.
Once approved, the Sender ID is added to the protected Sender ID register.
Let Dotdigital know about your protected Sender ID.
Global trend
Finland is not alone. The Sender ID registration approach reflects a broader international move towards sender verification:
Singapore – introduced in 2023.
Ireland – introduced in 2025.
Australia – introduced in 2026.
Austria – introduced in 2026.
Spain – introduced in 2026.
United Arab Emirates – alphanumeric Sender ID registration has been in place for many years.
Questions about Sender ID registration?
If you have questions about Sender ID registration or SMS sending in Finland, contact your Customer Success Manager or email us at support@dotdigital.com.
Learn more in Traficom’s SMS Sender ID guidance.