Bulk SMS in Australia: Spam Act and Sender ID Register Guide
Bulk SMS Australia guide: Spam Act consent, identify and unsubscribe rules, the ACMA SMS Sender ID Register and Unverified label, operators and SMS length.
By OmniChannels.ai Editorial Team · Reviewed by BroadNet Messaging Solutions Team
SMS & OTP
Short answer
To send bulk SMS in Australia, register your alphanumeric sender ID on the ACMA SMS Sender ID Register and authorise your provider, because unregistered IDs have been shown as "Unverified" since 1 July 2026. Under the Spam Act 2003 you also need consent before commercial texts, must identify your business and must honour unsubscribe requests within 5 business days.
On this page
- What rules apply to bulk SMS in Australia?
- What does the Spam Act require for SMS?
- How fast must you honour an unsubscribe?
- What changed on 1 July 2026 for sender IDs?
- How do you register an SMS sender ID in Australia?
- Which operators carry SMS in Australia?
- How should you separate OTP and promotional traffic?
- How does text affect SMS length in Australia?
- When should you send?
- A worked example: a veterinary group
- What should you check before your first Australian campaign?
- What are the common mistakes?
- How OmniChannels.ai helps
Key takeaways
- Since 1 July 2026, ACMA says SMS sent with an unregistered sender ID is shown to the recipient as 'Unverified'; registering the ID on the ACMA SMS Sender ID Register is how a brand name appears.
- The Spam Act 2003 sets three rules for commercial texts: consent (express or inferred), identification of the sender, and a working unsubscribe facility.
- Unsubscribe requests must be actioned within 5 business days, at no more than the usual cost to the person, and the facility must work for at least 30 days after the message is sent.
- Our regulation data lists alphanumeric sender IDs of 2 to 11 characters (not digits only), registration through a participating or certified provider, and a typical lead time of 5 to 10 business days.
- Telstra (505-01), Optus (505-02) and Vodafone Australia (505-03) are the networks in our coverage data, all with direct routes.
This guide is for marketing, retail, healthcare and operations teams that want to send business SMS in Australia: reminders, OTPs, delivery alerts and promotions. It explains the Spam Act 2003, the ACMA SMS Sender ID Register and what changed on 1 July 2026, which networks carry your messages and how to keep texts to one segment. It is a practical overview, not legal advice; confirm requirements with an Australian lawyer and your provider.
What rules apply to bulk SMS in Australia?
Two things apply: the Spam Act 2003 for what you send and to whom, and the SMS Sender ID Register for how your brand name appears. The Australian Communications and Media Authority (ACMA) is the regulator for both, according to our regulation data.
| Rule | What it covers | Where to check |
|---|---|---|
| Spam Act 2003 | Consent, identification and unsubscribe for commercial electronic messages | ACMA: dealing with spam |
| ACMA SMS Sender ID Register | Registered alphanumeric sender IDs; unregistered IDs labelled 'Unverified' | ACMA register page |
| Operators (Telstra, Optus, Vodafone Australia) | Routes, filtering, delivery | Through your provider |
What does the Spam Act require for SMS?
Three things: consent, identification and an unsubscribe facility. ACMA's guidance says the rules apply to commercial electronic messages, meaning messages that offer, advertise or promote goods or services. Messages that only influence a vote or opinion are rarely caught.
- Consent. A marketing sender needs prior consent, which can be express (the person actively agreed) or inferred from an existing relationship. Our regulation data states that the source of consent should be logged and reviewable.
- Identification. The message must make clear who sent it and include contact details.
- Unsubscribe. Every marketing text needs a clear way to stop. Our regulation data records a STOP keyword and a clearly stated unsubscribe on every marketing send.
Some senders, such as government bodies and registered charities, are exempt from the consent requirement, but ACMA says they must still include their contact details and a way to say stop. Check your own status with counsel.
Our opt-in consent generator drafts wording for sign-ups, and the guide to opt-in consent across channels explains record keeping.
How fast must you honour an unsubscribe?
Within 5 business days. ACMA's fact sheet says an unsubscribe request must be actioned within 5 working days, with no fee beyond the usual cost to the person of sending the reply, and the unsubscribe facility must work for at least 30 days after the message was sent. Our regulation data records the same 5 business day ceiling.
Treat the ceiling as the outer limit. Automatic handling of STOP the moment it arrives is easy to build, and ACMA's investigations have found businesses that kept sending after opt-outs. Keep one suppression list across numbers, campaigns and channels. The definition is in opt-out.
What changed on 1 July 2026 for sender IDs?
From 1 July 2026, SMS that uses an unregistered alphanumeric sender ID is shown to the recipient as "Unverified" instead of your brand name. This is ACMA's own wording: it says unregistered sender IDs are replaced with the word "Unverified", and that businesses must also contact each provider they want to send through and authorise it to use the registered ID. Third-party guides sometimes say unregistered traffic is blocked; ACMA's material describes the label, so rely on ACMA and your provider for the current position.
The effect on your results is practical: an "Unverified" label sits next to scam warnings in the same list of messages and can lower trust and response. Our regulation data matches: the ACMA SMS Sender ID Register, through a participating or certified provider, with unregistered IDs shown as Unverified since 1 July 2026.
How do you register an SMS sender ID in Australia?
Register the exact alphanumeric ID you send with, then authorise each provider that sends for you. Our regulation data lists alphanumeric IDs of 2 to 11 characters, not digits only, and a typical lead time of 5 to 10 business days.
| Step | What to do |
|---|---|
| 1. Decide the IDs | Use your brand or business name; plan separate IDs for transactional and promotional traffic if you want to measure them separately |
| 2. Prepare business details | Legal name and registration details, as the register requires |
| 3. Register | Apply on the ACMA register through a participating or certified provider |
| 4. Authorise providers | Link each provider you send through to the registered ID |
| 5. Test | Send to Telstra, Optus and Vodafone handsets and confirm the brand name shows |
Our sender ID letter generator drafts an authorisation letter, and the Australia sender ID page and sender ID checker show the current rules. If you want us to prepare and file the registration, see registrations; approval decisions stay with ACMA. For format background read SMS sender ID types.
Which operators carry SMS in Australia?
Three networks appear in our coverage data, each with a direct route:
| Operator | MCC-MNC |
|---|---|
| Telstra | 505-01 |
| Optus | 505-02 |
| Vodafone Australia | 505-03 |
Read delivery reports per operator, because a healthy blended figure can hide one weak network. Our guide to improving SMS delivery rates shows how to diagnose it.
How should you separate OTP and promotional traffic?
Send OTPs and service messages from their own sender ID and route, and promotions from another. A promotion in a login-code message makes it a marketing message and puts your codes at risk if the route is filtered.
| Traffic | Example | Practice |
|---|---|---|
| Transactional | OTP, appointment reminder, delivery update | Own sender ID; no promotion inside; any hour |
| Promotional | Offer, new service, loyalty message | Consent, identification, unsubscribe line |
| Mixed | "Your booking is confirmed. Get a free treat next visit" | Avoid; the offer makes it promotional |
Content and security for codes are covered in our OTP authentication messages guide.
How does text affect SMS length in Australia?
English text fits the default GSM 7-bit alphabet, so one message holds 160 characters (153 per part when split). Emoji and curly quotation marks switch the whole message to Unicode, which holds 70 characters (67 per part). Phone keyboards often insert a curly apostrophe automatically, which is a common reason for surprise extra segments. See GSM-7 and concatenated SMS.
These examples were counted against the limits (Southern Cross Vets is synthetic):
| Message | Encoding | Characters | Parts |
|---|---|---|---|
Southern Cross Vets: Reminder: Milo's check-up is Thu 12 Nov at 2:30pm. Questions? Call 02 5550 0142. Reply STOP to opt out. |
GSM-7 | 124 | 1 |
Southern Cross Vets: Spring dental checks are open. Book at scvets.example/b Reply STOP to opt out. |
GSM-7 | 99 | 1 |
Southern Cross Vets: Milo’s check-up is Thu 12 Nov at 2:30pm. Reply STOP to opt out. |
Unicode | 84 | 2 |
The third message is shorter than the first, yet it takes two parts because of one curly apostrophe in "Milo’s". Check final copy in the SMS character counter, and read SMS character limits and Unicode for other scripts.
When should you send?
We have not found a regulator-published time-of-day window for promotional SMS in Australia, and our regulation data records none. Agree sending hours with your provider, send promotions in the recipient's local daytime and mind the time zones from Perth to Sydney. OTPs and alerts can go at any hour. The send time planner helps schedule by local time, and SMS marketing rules by country compares markets.
A worked example: a veterinary group
"Southern Cross Vets" (synthetic) has 8 clinics in three states. It wants appointment reminders, a code for its pet portal and a seasonal check-up campaign.
- It registers one sender ID for reminders and codes and one for campaigns, and authorises its provider for both before launch.
- The sign-up form and front desk collect consent with the wording, date and number logged.
- Reminders and codes use plain text; the campaign avoids emoji and curly apostrophes so each message stays at one part.
- STOP replies are processed on receipt and feed one suppression list shared with email.
- It tests on Telstra, Optus and Vodafone handsets to confirm the brand name appears and not "Unverified".
What should you check before your first Australian campaign?
Work through this list in order, because the register and consent steps take the longest.
- Registration: the sender ID is registered on the ACMA register and your provider is authorised against it.
- Consent: every number on the list has a logged source, date and wording, and purchased lists are removed.
- Identification: each text starts with your business name, and contact details are available to the recipient.
- Unsubscribe: STOP is processed automatically, tested on all three networks and shared across campaigns.
- Encoding: final copy is counted for GSM-7 or Unicode and the part count is acceptable.
- Separation: OTPs and alerts use a different sender ID from promotions.
- Reports: delivery reports are read per operator after the first send.
What are the common mistakes?
- Sending with an unregistered sender ID after 1 July 2026, so the brand shows as "Unverified".
- Forgetting to authorise the provider on the register.
- Slow unsubscribes. The 5 business day limit is a ceiling.
- No consent evidence. Keep date, channel and wording.
- Smart quotes and emoji that double the segment count.
- Treating lead times as promises.
How OmniChannels.ai helps
OmniChannels.ai is powered by BroadNet, which has direct routes to Telstra, Optus and Vodafone Australia in our coverage data. We prepare and file sender ID registration with you, give per-operator delivery reports and support two-way SMS and SMPP 3.4 for high volume. For indicative list prices see the Australia SMS pricing page, then book a demo. Small team? Our SMS marketing guide for small businesses covers the basics.
Frequently asked questions
Is bulk SMS legal in Australia?
Yes, if you follow the Spam Act 2003 and register any branded sender ID. The Act applies to commercial electronic messages, including texts, and requires consent, sender identification and an unsubscribe facility. ACMA enforces it. This guide is general information, not legal advice, so confirm your program with an Australian lawyer.
What is the ACMA SMS Sender ID Register?
It is the register where organisations record the alphanumeric sender IDs they use. Registered IDs display as the brand name. ACMA says unregistered sender IDs are replaced with the word 'Unverified' from 1 July 2026. You also have to authorise each provider you want to send through, so ask your provider how to link yours.
Does the Spam Act apply to SMS?
Yes. ACMA treats SMS as a commercial electronic message when it offers, advertises or promotes goods or services. Such a message needs the recipient's consent, details identifying the sender and a way to unsubscribe. Some senders, such as government bodies and registered charities, are exempt from the consent requirement but still must identify themselves.
How fast must I process an SMS unsubscribe in Australia?
Within 5 business days, with no fee beyond the usual cost of sending the reply. ACMA's guidance also says the unsubscribe facility must work for at least 30 days after the message was sent. Process STOP replies automatically on the day you receive them, rather than treating five days as a target.
What consent do I need to send marketing SMS in Australia?
You need express consent, such as a sign-up the person actively made, or inferred consent from an existing relationship where the person could reasonably expect your messages. Our regulation data adds that the source of consent should be logged and reviewable. Keep the date, channel, wording and number for every contact.
How long does sender ID registration take in Australia?
Our published lead time is 5 to 10 business days. That is a typical range, not a promise, since decisions sit with ACMA and the register's processes. Missing business details add time, so prepare your company information and the exact sender ID text before you start.
Sources
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