At a glance: Australia’s SMS Sender ID Register, run by the ACMA, became mandatory on 1 July 2026. From that date, any text message sent to an Australian number with an unregistered alphanumeric sender ID (a branded name like “AcmeCo” instead of a phone number) has its sender ID replaced with the word “Unverified”, and messages carried by non-participating telcos are blocked. If your business sends branded SMS to Australia — including via AI agents — you must register each sender ID through every telco or messaging provider you send from, and (if you have an ABN) the ID must match your registered business name, company name, trademark or domain name.
Australia has switched on one of the most consequential changes to business SMS in years, and it lands squarely on outbound teams. The SMS Sender ID Register moved from voluntary to mandatory on 1 July 2026. The ACMA’s own site now carries a blunt banner: “SMS sent using unregistered sender IDs are now being labelled as ‘Unverified’.”
If your team runs SMS outreach at any volume — and especially if AI agents are composing and sending those messages — this is not a footnote. An unregistered sender ID now arrives on Australian phones stripped of your brand, stamped “Unverified”, and grouped into the same message thread as every other unverified sender, including scammers. Here is what changed, who has to act, and how to organise your response.
What the SMS Sender ID Register is, and how we got here
A sender ID is the short alphanumeric name at the top of a text message that shows who it is from — the ACMA gives “ATO”, “AusPost” and “myGov” as examples. Because every message from the same sender ID lands in a single thread on the recipient’s phone, scammers have long exploited spoofed sender IDs to inject fake messages into genuine brand threads. The ACMA reports that Australians lost more than $13.8 million to text message scams in the first nine months of 2025.
The register is the government’s structural answer, delivered as part of its Fighting Scams initiative. The legal machinery is the Telecommunications (SMS Sender ID Register) Industry Standard 2025, which binds every Australian telco that sends, transits or terminates SMS or MMS carrying sender IDs — the standard defines “telco” broadly to include carriers, carriage service providers and electronic messaging service providers (the messaging platforms most outreach teams actually use).
The key date was 1 July 2026. Businesses were told to register existing sender IDs before that date; telco enforcement obligations began on it. The rules are now in force.
What happens to unregistered sender IDs now
Under the industry standard, from 1 July 2026:
- Overstamping. Telcos that send or terminate text messages must overstamp all unregistered sender IDs with “Unverified”. Your brand name disappears from the message header entirely.
- Grouping. All “Unverified” messages are grouped together in a single thread on the recipient’s phone. Your carefully sequenced outreach shares a thread with phishing attempts. The ACMA’s consumer guidance is explicit that people “will likely treat unverified messages as scams”.
- Blocking. Telcos and messaging providers that have not been approved to participate in the register are prohibited from carrying SMS or MMS with sender IDs at all — the ACMA states that messages sent by non-participating providers “will be blocked”.
Note what is not affected: messages sent from an ordinary phone number (a long code) carry no alphanumeric sender ID and do not need registration. The register only governs branded alphanumeric headers.
Registered vs unregistered: what recipients see from 1 July 2026
| Registered sender ID | Unregistered sender ID | |
|---|---|---|
| Header shown | Your registered brand name (e.g. “AcmeCo”) | Replaced with “Unverified” |
| Threading | Own dedicated thread under your brand | Grouped with all other “Unverified” senders, including scams |
| Delivery | Carried by participating/certified telcos as normal | Blocked entirely if carried by a non-participating provider |
| Recipient trust | Consumers can be more confident the message came from you | ACMA guidance tells consumers to treat these with caution |
| Impersonation risk | Registration makes it much harder for scammers to impersonate your ID through participating telcos | Brand remains spoofable and indistinguishable from fakes |
Who must register, and how registration works
Any business or organisation sending branded texts to Australian numbers must register — the ACMA names SMEs, not-for-profits and agencies explicitly, and international organisations sending into Australia are covered too. Individuals, companies, partnerships, trusts, government entities and unincorporated associations can all hold registrations.
The process runs through your telco or messaging provider
You do not register directly with a government portal as your primary route. The ACMA’s process is:
- Contact each telco or messaging provider you send from. This matters for outreach teams using multiple SMS routes: you must register through every provider you use, and check each appears on the ACMA’s list of approved telcos and message providers.
- Provide the sender IDs you want registered. The provider registers them on your behalf. You must demonstrate a valid use case — the sender ID must match your identity and be clearly linked to your organisation.
- Pass verification. Your telco asks the ACMA to run checks on your organisation, your identity and your authority to act for the organisation. If you have an ABN, you will verify identity using myID, and the ACMA warns that your authorised contact or service-of-notice email in the Australian Business Register must be current before you apply.
Even if you self-register a sender ID, the ACMA is clear you must still also register it through each telco that will carry it — registration is how you authorise a specific provider to send under that ID.
Name-alignment rules: what IDs you can actually register
This is where teams get caught. If your organisation has an ABN, your sender ID must match your registered business name, company name, trademark or domain name. Without an ABN, it must match your trademark or your name on an official register in your home country. Shortened forms, acronyms and functional additions are allowed — the ACMA’s own examples are “Australia Post” registering “AusPost” and “ACMA” registering “ACMA Alerts”.
Format rules also apply: 2–11 characters, letters/numbers/standard symbols only, not numbers-only, no leading or trailing spaces or underscores, nothing offensive or misleading, and certain restricted words cannot stand alone. Sender IDs are not case sensitive, and the same ID can be registered by multiple organisations if each proves a valid use case.
What this means for AI-driven SMS outreach specifically
Teams running autonomous or semi-autonomous outreach have a few extra things to think through.
Inventory every route your agents send through
AI outreach stacks often send SMS through more than one messaging provider — a primary API, a CRM’s built-in SMS, a regional failover. Registration is per provider, so an ID registered with provider A still gets overstamped when the same campaign fails over to unregistered provider B. If your platform orchestrates channels the way multi-channel orchestration systems do, map every SMS egress path before assuming you are covered.
Sender identity must be consistent across channels
The register rewards brands whose identity is coherent: the name on the SMS should match the name your voice agent uses on calls, the domain in your emails and your registered business name. That alignment is no longer just good practice — for SMS it is a registration criterion. It also compounds trust: when a prospect has spoken to your AI voice agent and then receives a text from the same recognisable brand name, the thread continuity does real work. A message from “Unverified” after a branded phone call does the opposite.
Trust labels now sit between you and your reply rates
Outbound reply rates are already under pressure as AI-generated volume rises — we have written about why reply rates fall as AI outbound volume grows — and a government-mandated “Unverified” stamp is about as strong a negative trust signal as a channel can attach. The ACMA is actively teaching Australian consumers to treat unverified messages as probable scams. An unregistered outreach programme is now competing not just against inbox fatigue but against explicit public warnings.
The Spam Act still applies on top
Registration verifies who you are; it does not make a message lawful. The Spam Act 2003 still requires consent (express or inferred) before you send commercial messages, accurate sender identification in the message body, and a functional unsubscribe — the ACMA specifies honouring opt-outs within 5 working days and keeping the mechanism working for at least 30 days. One practical wrinkle the ACMA flags: alphanumeric sender IDs generally cannot receive replies, so “Reply STOP” alone does not work from a branded ID — you need an alternative opt-out path. Our guide to outreach compliance for AI agents covers the Spam Act alongside TCPA and GDPR, and the register joins Australia’s broader tightening of automation rules alongside the ADM transparency requirements.
To be clear about our own lane: platforms like Zian AI orchestrate what gets said, on which channel, and when — registration itself is something your business does with its telco or messaging provider, and no software can do the identity verification for you.
Action checklist for outreach teams
- Audit your sender IDs. List every alphanumeric ID currently in use across campaigns, CRMs, transactional systems and AI agent flows targeting Australian numbers.
- Map your providers. Identify every telco or messaging provider that carries your SMS, and confirm each is on the ACMA’s approved list. Replace any that are not participating — their sender-ID traffic is blocked.
- Check name alignment. Confirm each ID matches your registered business name, company name, trademark or domain name, and meets the 2–11 character format rules. Rename IDs that will not pass.
- Update the ABR first. Make sure your authorised contact or service-of-notice email in the Australian Business Register is current — the ACMA uses it during verification.
- Register through every provider you use, and be ready to complete myID identity verification when the ACMA’s checks come through.
- Fix your opt-out path. Because branded sender IDs generally cannot receive replies, ensure every message includes a working unsubscribe alternative, and honour requests within 5 working days.
- Watch deliverability. After 1 July 2026, monitor delivery and reply metrics for any route still being overstamped or blocked, and tell customers which sender ID your messages will come from so they can spot impersonators.
FAQ
When did the SMS Sender ID Register become mandatory?
1 July 2026. From that date, the ACMA’s rules require telcos to overstamp unregistered alphanumeric sender IDs with “Unverified”, and only providers approved to participate in the register may carry SMS or MMS with sender IDs at all. The ACMA confirms this on its SMS Sender ID Register page, which states that from 1 July 2026 texts sent with a branded sender ID need that ID registered, and that unregistered sender IDs are now being labelled “Unverified”.
Do I need to register if I send SMS from a normal phone number?
No. The register covers alphanumeric (branded) sender IDs only. The ACMA states that if you do not use a sender ID, or you send messages from a phone number, you do not need to do anything. Messages from long codes continue to work as before — though the Spam Act’s consent, identification and unsubscribe rules still apply to any commercial message.
Can I register any brand name I like as a sender ID?
No. If you have an ABN, the sender ID must match your registered business name, company name, trademark or domain name; shortened versions, acronyms and additions like “Alerts” are acceptable if clearly linked to your organisation. IDs must be 2–11 characters, cannot be numbers-only, cannot contain the word “Unverified”, and cannot consist solely of restricted words.
What happens to messages I send through a provider that isn’t in the register?
They are blocked. The ACMA states that telcos and message providers not approved to participate are prohibited from sending, transiting or terminating SMS/MMS with sender IDs, and that messages sent by non-participating providers will be blocked. Check your provider against the ACMA’s list of approved telcos and message providers before your next campaign.
Does registering a sender ID make my SMS outreach compliant with Australian law?
No. Registration verifies your identity and protects your brand header, but the Spam Act 2003 separately requires consent before sending commercial messages, accurate identification of your business in the message, and an easy, functional unsubscribe. Both regimes apply at once, and both are enforced by the ACMA.
Does an AI outreach platform register sender IDs for me?
No — registration is done by your business through each participating telco or messaging provider, with identity checks conducted via the ACMA. An outreach platform can route messages and orchestrate channels, but the verification of your organisation, your identity and your authority to act is yours to complete.
Where this fits for growing teams
The register is genuinely good news for legitimate senders: once registered, your brand header becomes far harder to spoof through participating telcos, and the “Unverified” stamp pushes scammers out of your thread. Teams that treat sender identity as an asset — one consistent, registered, recognisable name across SMS, voice, email and WhatsApp — will see the trust dividend in reply rates that unregistered senders lose.
Zian AI is built for that multi-channel world: autonomous AI sales agents working across phone, SMS, email and WhatsApp in 30+ languages, with SmartReach AI™ orchestrating message, channel and timing by country, industry and profile. Zian AI is in waitlist beta and will partner with teams that want outbound scale without sacrificing sender identity. You can read more in the Zian AI FAQ.