SMS Marketing in Australia: Rules, Costs & How to Do It Well

SMS reaches effectively every mobile in Australia, gets read within minutes, and — since 1 July 2026 — operates under a mandatory ACMA sender ID registration regime that most overseas guides don't even mention. This is the working Australian guide: the regulatory layer (sender IDs, Spam Act consent, opt-out mechanics), the technical layer (encoding, segments, routing), the cost logic, and the campaign patterns that perform. For rich media — images, GIFs, video — see the companion MMS guide; for choosing between them, MMS vs SMS.

Last reviewed: 22 August 2026.

The regulatory layer comes first

Australian SMS marketing is shaped by two regimes, and both are enforced:

• The Spam Act 2003 requires consent before you send, sender identification in the message, and a functional opt-out. ACMA actively issues infringement notices — the running penalty tracker and pre-send checklist live in our Australian messaging compliance hub.
• The ACMA SMS Sender ID Register — mandatory since 1 July 2026 — requires alphanumeric sender IDs (your brand name in the "from" field) to be registered. Unregistered alphanumeric IDs are subject to blocking as an anti-scam measure. If you send from a dedicated number instead, the register doesn't apply to you; if your brand name is the sender, it must be registered before campaigns route reliably.

Practical consequence: decide your sender identity early. A registered alphanumeric sender ID maximises brand recognition but can't receive replies; a dedicated virtual number supports replies (and is required for MMS) and builds recognition over time. Many programs run both — number for conversational and transactional, registered ID for one-way brand broadcasts.

The technical layer: what an SMS actually is

The encoding trap is the expensive one: paste copy from a word processor and a single curly apostrophe silently converts your 155-character message from one GSM-7 segment into three unicode segments. Lint your copy for non-GSM characters before every send.

Cost logic

SMS is priced per segment, per recipient. The levers that actually move program cost:

1. Segment discipline. One segment vs two is a 50% cost difference at identical reach. Write to 160 GSM-7 characters including the opt-out.
2. List hygiene. Sends to disconnected numbers still cost money. Delivery-receipt data should feed automatic suppression.
3. Targeting over broadcast. The 10 deadly SMS mistakes pattern holds: smaller, better-targeted sends outperform sprays on revenue per message, not just cost.
4. Channel mix. SMS for urgency and confirmations; step up to MMS where visual persuasion pays — the comparison guide covers the crossover math.

Campaign patterns that work in Australia

• Flash/urgency offers — SMS's read-within-minutes behaviour is the channel's structural advantage; send when the offer window is real.
• Abandoned cart and browse recovery — triggered, personalised, and measurable end to end with click-tracked links.
• Transactional plus — delivery updates and confirmations earn the inbox trust that marketing sends spend. Keep the legal classification honest (the transactional flag is a compliance boundary, not a deliverability trick).
• Two-way keywords — competitions, opt-in, support triage on a dedicated number.
• A/B tested copy — test one variable at a time; at SMS volumes, copy differences reach significance fast.

Personalisation raises every one of these: personalised text messaging merges customer data into copy (and, on MMS, into the creative itself).

Sending at scale

Marketers run campaigns through the intouch platform or trigger them from their existing stack — Salesforce Marketing Cloud Journey Builder natively, or any system via the REST API. Delivery receipts, click data and opt-outs flow back either way, so suppression and reporting stay in your source of truth.

FAQ

Do I need to register my SMS sender ID in Australia? If you send from an alphanumeric sender ID (a name, not a number) — yes, registration under ACMA's SMS Sender ID Register has been mandatory since 1 July 2026. Sends from dedicated numbers don't use the register.

How many characters is one SMS? 160 in standard GSM-7 encoding, or 70 if any unicode character appears. Longer messages are split and billed per ~153-character segment.

Is SMS or MMS better for marketing? Different jobs: SMS for urgency, confirmations and cost-sensitive scale; MMS for visual persuasion and offer-led campaigns where engagement rates justify the higher per-message cost. See MMS vs SMS.

Can customers reply to marketing SMS? Only if you send from a dedicated virtual number. Alphanumeric sender IDs are one-way — you must still provide a working opt-out mechanism (e.g. a reply-capable number or link), which is a Spam Act requirement either way.

What consent do I need before sending marketing SMS? Express or inferred consent under the Spam Act 2003, plus sender identification and functional opt-out in every message. The compliance hub has the practitioner detail and ACMA penalty tracker.