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ACMA Sender ID Changes: What Businesses Must Do (2025)

  • Hosanna Neri
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Changes are coming to the way SMS & MMS messaging operate in Australia. It is likely, from 15 December 2025, unregistered Sender IDs will be replaced with “Unverified.” Here’s what it means, why it matters, and how your business can prepare.

Summary

  • At this stage, from 15 Dec 2025, unregistered Sender IDs will display as “Unverified.”
  • Registrations open 30 Nov 2025 with enforcement two weeks later.
  • The changes aim to protect Australians from SMS scams.
  • Businesses must register their Sender IDs via an authorised entity (like Tall Bob).
  • Start preparing now by checking your ABR details and auditing all your Sender IDs.

Tall Bob is here to help you navigate these changes. Talk to our team today to ensure your Sender IDs are ready before the deadline.

ACMA Sender ID Register: What It Means for Your Business

The Australian Communications and Media Authority (ACMA) is tightening the rules around how businesses use Alphanumeric Sender IDs (the name that shows up when your customers receive an SMS or MMS from you).

It is likely that from 15 Dec 2025, if your Sender ID isn’t registered and approved, your messages will no longer display your brand name. Instead, they’ll be replaced with a generic label: “Unverified.”

For any business that relies on SMS or MMS for customer engagement, marketing, or service updates, this change is critical. Not only could it impact your customer trust, it could also disrupt how your messages are delivered and read.

Why Is ACMA Making This Change

Put simply: scammers are becoming more sophisticated.

  • In 2024, ScamWatch received 77,365 reports of SMS scams, resulting in losses exceeding $14 million.
  • By May 2025, SMS scam losses had jumped 79% compared to the same month in 2024.
  • SMS now accounts for 31% of all reported scams across communication channels.

Scammers often impersonate trusted brands, such as banks, retailers, or government bodies, using fake sender names. By introducing the Sender ID Register, ACMA aims to protect Australians by ensuring that only verified businesses can use branded sender names.

ACMA Changes 2025: An example of legitimate messages vs scam messages.

An example of a message thread with the alphanumeric sender ID, legitimate messages vs scam messages pretending to be from the legitimate sender.

The result? Messages sent from unregistered IDs will be automatically flagged as “Unverified” and grouped in a separate inbox on customer devices.

When Are the Changes Happening

Here’s the current timeline for the rollout:

  • 30 Sep 2025 – ACMA finalises the rules supporting the register (delayed from July to allow more industry consultation).
  • 15 Oct 2025 – Onboarding begins for telcos.
  • 30 Nov 2025 – Businesses can start registering their Sender IDs through entities like Tall Bob.
  • 15 Dec 2025 – The register goes live. Any SMS/MMS sent using an unregistered ID will show as “Unverified.”

It’s a tight window—just two weeks from when registrations open to when enforcement begins.

ACMA Changes 2025: An example of how an unverified alphanumeric sender ID from 15 Dec.

An example of how an unverified alphanumeric sender ID would look like in a recipient’s handset from 15 Dec 2025 onwards.

How Will the Process Work

The finer details are still being finalised, but here’s what we know so far:

  • Businesses will need to register their Sender IDs through an authorised entity.
  • Registration will involve verifying both the purpose of the Sender ID and the identity of the person making the request.
  • Approval will rely on two checks:
    • Business verification – the details of the entity requesting a Sender ID must match what’s recorded on the Australian Business Register (ABR).
    • Authorised Representative verification – the details of the entity requesting a Sender ID must match what’s recorded on the Australian Business Register (ABR).

For organisations that don’t have an ABN, ACMA has flagged that a pathway will be available for Sender ID registration, but the exact process has not yet been finalised.

Alphanumeric Sender IDs will also need to meet ACMA’s rules, including:

  • 2–11 characters long
  • Must contain at least one character which is not a number
  • No spaces or underscores at the start or end of the Sender ID
  • No offensive, misleading, or restricted words (like “Unverified”)
  • Must directly relate to your business name, trademark, or domain

Abbreviations and shortened forms are allowed, e.g. “AusPost” for Australia Post.

What Should You Do Next

  • Audit your Sender IDs – Identify all the IDs you’re currently using—including seasonal or low-frequency ones.
  • Update your ABR details – Make sure your registered business information is accurate and aligned with your sender name.
  • Plan ahead – With only two weeks between registration opening and enforcement, early preparation is critical to avoid disruption.

At Tall Bob, we’ll keep you updated every step of the way, working closely with the telcos and relevant bodies to ensure your messaging remains compliant, visible, and trusted.

Frequently Asked Questions

General

  • What is this Sender ID Register all about?

    It’s ACMA’s new system to stop SMS scams. At this stage, from 15 Dec 2025, all alphanumeric sender IDs in Australia must be registered or they’ll be shown as “Unverified.”

  • Why is ACMA introducing these changes?

    Because of the effectiveness of the SMS channel, it is now one of the top channels used by fraudsters and scammers in Australia. The Sender ID Register is designed to protect consumers and restore trust in SMS by ensuring only verified businesses can use branded Sender IDs.

  • Are personal one-to-one SMS impacted?

    No, personal mobile-to-mobile SMS (just you texting a friend) are unaffected. The register applies only to business or agency SMS/MMS using alphanumeric sender IDs to represent a business.

  • What about messages sent to numbers outside of Australia?

    These changes only apply to messages sent to Australian mobile numbers; if you are sending messages to other countries these rules do not apply.

  • What if I send messages from a numeric Sender ID (long code)?

    If you are sending messages from a long code these changes do not affect you, the Sender ID Registry targets Alphanumeric Sender Addresses only.

  • What are the Alphanumeric Sender ID format rules?

    Length: Between 2 and 11 characters long

    Characters: Use ASCII characters (decimal codes 32–126), which includes letters (A-Z, a-z), numbers (0-9), and the space character 

    Format: Cannot start or end with a space or an underscore

    Exclusions: Cannot consist solely of numbers

  • How is Tall Bob supporting customers through this?

    We are and will continue to work with the telcos and relevant bodies to stay ahead of the changes. Once registration opens, Tall Bob will guide customers through the process, making sure IDs are compliant, verified, and ready well before the deadline.

Registration Process

  • When do I need to register?

    At this stage, it looks like businesses will have a tight window, between the 30 Nov to 15 Dec 2025, to register sender IDs, or risk disruption.

  • Who must register?

    Any sender—individuals, corporations, trusts, partnerships, government entities—can register, with a registered “Authorised Representative” who must be on the ABR if they hold an ABN.

    For non-AU ABN holders and international entities, “Authorised Representative” do not need to be on the ABR Register, but will need to undergo some other form of identity verification (exact process is still pending).

  • What must be provided for registration?

    You’ll need:

    Your entity name + ABN (or equivalent)

    Authorised representative’s contact, matching ABR details

    A use case showing your sender ID is tied to your business name, trademark, domain, or an accepted abbreviation.

  • What if my business doesn’t have an ABN?

    Non-ABN entities must go through a certified telco or partner. They’ll handle verifications, but you won’t have direct ACMA access.

  • Can international businesses register Sender IDs?

    Yes, international entities can participate but only through certified Australian telcos or authorised partners. They must go through ACMA-approved carriers to register their sender IDs.

  • What happens if I don’t register my Sender ID?

    If your Sender ID is not registered, your SMS or MMS messages will no longer display your business name and those messages may be grouped into a separate inbox—risking visibility, trust, and engagement.

  • What if I send messages on behalf of my clients?

    If you are a software or SMS reseller, and you send messages on behalf of clients, then these changes may impact you differently.

    The ACMA standard proposes that all businesses that hold an ABN, and are classified as a telco will be responsible for participating in the register, broadly a telco under the standard will include Carriers, Carriage Service Providers (CSP) and Electronic Message Service Providers (EMSP):

    • A Carrier is a business that operates a mobile network; Optus, Telstra, Vodafone, etc.
    • A Carriage Service Provider is a business that provides mobile services to the public using a carriers infrastructure; VOIP Providers, Virtual Telcos (Amaysim, Boost etc) SMS Aggregators (Tall Bob).
    • An Electronic Messaging Service Provider (EMSP) is a service provider that facilitates sending SMS or MMS messages on behalf of other businesses, through for example a SaaS or CRM Platform, they generally do so by connecting to businesses like Tall Bob.  (In general if you supply SMS or MMS services to the public and you don’t fall under the first two definitions you probably fall under this one).


    The standard in regards to this is yet to be finalised, we can provide only general advice around this and would encourage you to review the information provided directly from the     ACMA, and to seek legal advice on your own unique circumstances.

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