Most channel guides start with strategy. SMS in Singapore does not let you. Before you write a word of a campaign there is a registry you must join, a fee you must pay, a name you must be granted and a two-to-three-week wait — and if you skip it, your message lands on your customer’s phone under the header “Likely-SCAM”.
The second surprise is stranger. The statute governing the content of a marketing SMS requires you to give the recipient a mobile telephone number they can text back to unsubscribe. The registry pushes you towards sending from a short brand name like “ACMESG” — which is not a phone number and cannot receive a reply. Two Singapore regimes, one message, opposite instructions.
This guide covers both layers: the SMS Sender ID Registry, what it costs, what it will let you call yourself, why a registered Sender ID still fails to arrive, and the Spam Control Act and PDPA duties that bite once it does. It is the companion to our guide on WhatsApp marketing and the two statutes that disagree about it, and the two channels turn out to be governed almost inversely. General information, not legal advice.
The gate: you cannot send a branded SMS in Singapore without joining a registry
The Singapore SMS Sender ID Registry (SSIR) was set up in March 2022 and is operated by the Singapore Network Information Centre (SGNIC), a wholly-owned subsidiary of IMDA. Its purpose is anti-spoofing. In October 2022 IMDA finalised the Full SSIR Regime: from 31 January 2023, every organisation intending to use an alpha, numeric or alphanumeric Sender ID in SMS to Singapore mobile users must first register it through the SSIR portal. SGNIC’s statement of what happens otherwise is blunt — “All non-registered Sender IDs will be marked as ‘Likely-SCAM’.”
Read that as a marketer rather than a compliance officer. An unregistered campaign does not simply underperform: it arrives inside the same thread the phone uses for genuine scam traffic, beside the fake parcel notifications and fraudulent bank alerts. There is no version of that which converts.
Three planning constraints follow. You need a Singapore UEN from ACRA or another Singapore agency, so a foreign business can only register through a local subsidiary or branch office. You need an IMDA-licensed aggregator chosen before you apply, because the application asks you to name the Participating Aggregators you work with. And you need Corppass, for verification.
What it costs, and the two deadlines that quietly destroy work
SGNIC publishes its fees, which makes SMS one of the few marketing channels in Singapore with a fixed, public entry cost: a one-time account set-up fee of S$545 per registered organisation, and an annual listing fee of S$218 per registered Sender ID, both inclusive of GST. The annual fee being per Sender ID matters — a business wanting “ACME” for transactional messages and “ACMEPROMO” for marketing pays twice, every year, forever.
Two deadlines sit inside the process, and both are unforgiving. You have 30 calendar days to pay once SGNIC accepts an application: miss it on an account and you start again; miss it on a Sender ID and, in SGNIC’s own wording, it “will be released i.e. available for another user to register”. And renewal is a cliff, not a grace period — if the annual payment is not made by the last day of the validity period, the Sender ID is automatically removed and must be re-registered first-come-first-served. That produces a risk most marketing teams have never modelled: an unpaid S$218 invoice can put your brand’s Sender ID back into an open queue. Put that date in the same calendar as your domain renewals.
Two details before you budget. Payment is Visa, Mastercard or PayNow dynamic QR only inside the portal — no GIRO, no bank transfer — and payments are non-refundable, with no editing after payment: register “ACMESG” when you meant “ACME SG” and you delete it and pay again. On timing, SGNIC’s guidance is that the whole process from account registration to the commencement of protection typically takes about 19 calendar days — which makes that number your critical path, not the creative deadline.
What you are allowed to call yourself
The Rules of Registration are more restrictive than most brand teams expect. An alphanumeric Sender ID must have a minimum of 3 and a maximum of 11 characters, contain no non-Latin characters, carry no leading or trailing spaces, use only the special characters in the Rules’ annex, and must not be generic in nature (SGNIC’s own examples are “OTP” and “SMS”), sensitive in nature, or suggestive of a link to the Singapore Government, statutory bodies, regulatory authorities or national movements.
Two further rules matter commercially: no sharing of Sender IDs between organisations, and no transfer between organisations unless SGNIC approves it. A group with three operating companies is potentially three accounts and three sets of fees. And where a Sender ID does not obviously relate to your name or business, SGNIC may ask you to justify it with a website, screenshots or marketing collateral, so an aspirational campaign name is harder to register than your trading name. The 11-character ceiling bites too: “Singapore” alone is nine characters, so many SME names do not fit and the Sender ID becomes an abbreviation — a new brand asset customers must learn to trust. Choose it once and never change it.
The defensive registration almost nobody uses
The genuinely underused part of the SSIR is that there are two kinds of registration. A Whitelist (WL) Sender ID is the one you send from, conveyed onward by mobile network operators and participating aggregators. A Blacklist (BL) Sender ID is defensive: SGNIC’s description is that BL Sender IDs “will be blocked by mobile network operators and/or SMS aggregators from sending SMS message to mobile subscribers.”
SGNIC spells out the use case. If you have registered “XYZ” as a WL Sender ID, plausible variants include “XYZ SG”, “XYZ Info”, “XYZ Service” and “XYZco” — registering those as BL Sender IDs stops anyone else using them. There must be a nexus between the BL Sender ID and your organisation, and both types can sit in one account.
Treat it as defensive domain registration for the SMS channel, and price it the same way, since each BL Sender ID carries the same annual fee. For a brand that is actually impersonated, blacklisting the two or three most convincing near-misses is cheaper than anything available afterwards, and it sits alongside the trademark and platform routes in our guide to brand impersonation and fake reviews in Singapore.
Six reasons a registered Sender ID still does not arrive
This is the section to keep, because it turns up as an emergency at 9am on campaign day. SGNIC publishes a troubleshooting list for organisations whose registered messages are still converted to “Likely-SCAM” or blocked, condensed here with the marketing consequence attached:
| Cause | What it looks like | What to do |
|---|---|---|
| 1. Whitelisting not yet effective | Accepted but still pending; sending before the effective date converts the message | Check the portal reads “Live” with a date in the “Effective By” column before scheduling |
| 2. Case mismatch | Sender IDs are case sensitive — SGNIC’s example is that “PineApple” and “PineAPPLE” are two different IDs | Match the registered casing exactly, or register each casing you use |
| 3. An unregistered Sender ID in the mix | Only one of several Sender IDs was registered, or a vendor sends under theirs | Inventory every Sender ID your stack sends under, vendors included |
| 4. A non-participating aggregator | A whitelisted Sender ID routed outside the SSIR — SGNIC states these will be blocked | Check the published Participating Aggregators list before adding a vendor |
| 5. Incomplete aggregator onboarding | SSIR done, but the aggregator’s own KYC documents were never returned | Treat aggregator onboarding as a second, separate approval |
| 6. No test send | The whole list goes out and a customer finds the failure | Test-send to your own numbers before every campaign, not just the first |
Cause 3 catches growing businesses. The SSIR is registered per organisation, but SMS is sent by whichever tool happens to send it — and by year three most SMEs have four or five: the CRM, the appointment reminder system, shipping notifications, the review-request tool and the campaign platform. Our guide to choosing a CRM for a Singapore SME covers the same consolidation problem on the data side. Cause 4 has a second implication: your Sender ID is tied to the aggregators you named, so switching SMS vendors is not a purely commercial decision.
Now the law: what applies to SMS that does not apply to WhatsApp
With the gate passed, two Singapore regimes govern the message itself. They are the same two that govern WhatsApp, but they land differently — and the differences run opposite to what most people assume.
The PDPA’s Do Not Call provisions
Section 43(1) of the Personal Data Protection Act 2012 prohibits sending a specified message to a Singapore telephone number unless you have checked the relevant Do Not Call Register and confirmed the number is not listed, or you hold clear and unambiguous consent evidenced in written or accessible form. An SMS is the paradigm case, so the DNC obligations apply in full and per message. There is no volume threshold: one marketing SMS to one unchecked number is enough.
This is exactly where SMS and WhatsApp part company. Section 4A of the Spam Control Act provides that where a message is sent to an instant messaging account whose identifying name is a mobile telephone number, it is not a message sent to that number. SMS has no such provision, because there is no intermediary account — the number is the address. The consent and record-keeping mechanics are in our guide to PDPA, consent and marketing tracking.
The Spam Control Act, including the label that does apply
The Spam Control Act 2007 is triggered by bulk, not by a single message. Section 6 deems messages sent in bulk where a person sends more than 100 with the same or similar subject matter in 24 hours, more than 1,000 in 30 days, or more than 10,000 in a year. Section 11 then requires bulk senders of unsolicited commercial electronic messages to comply with the Second Schedule, and this is where the common advice inverts.
The <ADV> label applies to SMS. Paragraph 3(1)(b) requires the letters “<ADV>” with a space before the title in the subject field, “or if there is no subject field, in the words first appearing in the message”. Paragraph 3(3) disapplies the whole of paragraph 3(1) only for messages sent to an instant messaging account — and SMS is not one. So the label that does not belong on a WhatsApp broadcast does belong at the very start of a bulk marketing SMS. The same paragraph also requires header information that is not false or misleading, and an accurate, functional contact email address or telephone number.
The unsubscribe facility applies in an SMS-specific form. Paragraph 2(1) requires an unsubscribe address plus a statement that the recipient may use it; 2(3) makes the SMS version specific, which creates the problem in the next section. The mechanics: the statement must be clear, conspicuous and in English (2(4)); the address must stay valid and able to receive requests for at least 30 days after sending (2(5)); using it must not cost more than the usual cost of that kind of address (2(6)); nothing further may go out after 10 business days from the request (2(7)); and request data must not be disclosed without consent (2(8)).
Enforcement splits. DNC contraventions are a PDPC matter attracting financial penalties. The Spam Control Act is enforced by private civil action: section 13 lets anyone who suffered loss or damage sue the sender, and section 14 lets the claimant elect statutory damages not exceeding $25 per message, capped in aggregate at $1 million unless actual loss exceeds it.
The collision: the statute wants a reply number, the registry wants a brand name
Put paragraph 2(3) next to the Rules of Registration and a genuine conflict appears. It says that where an unsolicited commercial electronic message is received by text sent to a mobile telephone number, the message must include “a mobile telephone number to which the recipient may submit an unsubscribe request by text”. Not a URL. Not an email address. Not a keyword.
An alphanumeric Sender ID cannot do this. “ACMESG” is not a mobile telephone number, and on most handsets a reply to it either fails or goes nowhere your systems can read. The whole point of the SSIR — a short, brand-owned Sender ID — is architecturally incompatible with the statute’s preferred unsubscribe route for the same channel. There are three ways through, and only one is clean.
- Register a Long Virtual Number (LVN) as your Sender ID. The SSIR permits numeric Sender IDs assigned by a Singapore mobile network operator and sent by a Participating Aggregator, from the 8 and 9 series, in 10-digit form with the 65 prefix and no “+” (e.g. 658xxxxxxx). Two conditions: a SIM card mobile number cannot be registered, and the LVN must be unique to your organisation, with documents showing an MNO issued it to your aggregator. It is a real number, so it can receive a reply and satisfies paragraph 2(3) directly. What you give up is the brand name in the header.
- Register a 5-digit shortcode. Only those starting with 7, unique to your organisation, with documentation that an MNO issued it to your aggregator. Replyable and short, but not a “mobile telephone number” on the plain reading of 2(3), so a weaker fit.
- Send from the alphanumeric Sender ID and print a reply number in the body. The common approach, and the one that costs characters.
For an SME running real bulk marketing SMS, the honest recommendation is to run two Sender IDs deliberately: the alphanumeric one for transactional and service messages, where the Second Schedule’s duties generally do not arise, and an LVN for marketing campaigns, where they do. That is a second annual listing fee, and the cheapest way to stop the two regimes fighting inside one message.
The 160-character budget, worked
Compliance on SMS is not an abstract obligation, it is a character count. A standard GSM-7 SMS is 160 characters; go over and it becomes a concatenated message most aggregators bill as two. Here is where a compliant bulk marketing SMS spends its budget:
| Element | Source of the requirement | Typical cost |
|---|---|---|
| “<ADV>” at the very start, with a space | Second Schedule para 3(1)(b) | 6 characters |
| Who you are (the Sender ID may be an abbreviation the recipient does not recognise) | Para 3(1)(c)–(d): header not misleading, functional contact | 8–15 characters |
| The unsubscribe statement, in English, clear and conspicuous | Para 2(1)(b) and 2(4) | ~25 characters (“Reply STOP to unsubscribe”) |
| A mobile telephone number to reply to, if you are not sending from an LVN | Para 2(3)(a) | ~13 characters |
| Shortened tracking link | Commercial | ~23 characters |
| Left for the actual offer | ~78–85 characters | |
Roughly half the message is structural — the real reason so much Singapore marketing SMS reads badly is a budget spent before the copywriter arrived. Two moves recover most of it: sending from a registered LVN removes the separate reply number, because the Sender ID is the reply number; and moving detail behind a link converts characters into a click you can measure, the discipline we apply to tracking calls and messaging leads.
Your agency is inside the liability, not beside it
Two provisions make this a shared exposure. Section 12(1) of the Spam Control Act prohibits aiding, abetting or procuring a contravention of section 11, inducing one, being “in any way, directly or indirectly, knowingly concerned in or a party to” one, or conspiring to effect one. Section 12(2) carves out only those providing facilities for online services or network access, or connections for routing data. An agency that builds the list, writes the copy and presses send is not a connectivity provider — and section 13 lets an aggrieved recipient sue a person who contravened section 12(1) directly.
Then the registry. SGNIC’s own example of when a Letter of Authorisation is needed is “a marketing firm is appointed by an organisation to run a marketing campaign for the organisation”, issued by the organisation that registered the Sender ID and given to the Participating Aggregator handling the send. So an agency cannot own your Sender ID; it is authorised to use yours, per aggregator. Three things follow: the Sender ID stays in your name, so check whose UEN any vendor-run SSIR account sits under; the LOA is per aggregator, so a vendor switch means a new one; and consent evidence has to travel, because if the agency sends but you hold the records, neither party alone can demonstrate compliance. That is one of the practical tests in our list of agency red flags to watch for in Singapore.
SGNIC also warns that scammers take over poorly secured SMS accounts held with aggregators, and its advice is concrete: rotate credentials and API keys, keep keys in a managed store under a named owner, remove decommissioned keys, enforce two-factor authentication on admin access, ask about IP whitelisting, and set a daily volume cap or alert — the cheapest control on the list. If it goes wrong, our guide to data breach rules for marketers comes next.
Where SMS actually earns its place
SMS has three properties nothing else has: it needs no app, login or data connection; it reaches the one screen a person checks unprompted; and no algorithm decides whether to show it. That points at a narrow set of uses — time-critical service messages such as appointment reminders and delivery windows, which are generally not unsolicited commercial messages sent in bulk (attach an upsell and that changes); time-boxed offers to a base that consented specifically to SMS; and customers your other channels miss. It does not suit prospecting, where DNC checks apply per message and 160 characters has no room to build a case — that is a job for paid social or search — nor nurture, where email gives far more room per dollar. Decide which case you are before you register, because the 19-day timeline means you cannot decide later. Attribution for an SMS-driven visit or call is covered in our performance marketing guide, and the results are in our Singapore case studies.
Frequently asked questions
Do I need to put <ADV> on a marketing SMS in Singapore?
If you are sending unsolicited commercial messages in bulk, yes. Second Schedule paragraph 3(1)(b) of the Spam Control Act requires “<ADV>” with a space before the title in the subject field, or where there is no subject field — the SMS case — in the words first appearing in the message. Paragraph 3(3) disapplies 3(1) only for messages sent to an instant messaging account, which SMS is not, so this is the opposite of the WhatsApp position. “In bulk” is section 6: more than 100 messages with the same or similar subject matter in 24 hours, more than 1,000 in 30 days, or more than 10,000 in a year.
What does it cost to register an SMS Sender ID in Singapore?
SGNIC charges a one-time account set-up fee of S$545 per registered organisation and an annual listing fee of S$218 per registered Sender ID, both inclusive of GST. Payment is Visa, Mastercard or PayNow dynamic QR only inside the SSIR portal, must be made within 30 calendar days of acceptance, and is non-refundable.
What happens if I do not register my Sender ID?
Under the Full SSIR Regime, in force since 31 January 2023, all non-registered Sender IDs are marked “Likely-SCAM” — the message arrives, but under a header telling the recipient it may be a scam. Separately, SGNIC states that whitelisted Sender IDs routed through an aggregator not participating in the SSIR will be blocked.
Can my agency register the Sender ID for me?
No. Registration is tied to your organisation’s ACRA UEN and Corppass, and Sender IDs may not be shared between organisations or transferred without SGNIC’s approval. An agency can send on your behalf using a Letter of Authorisation, issued by the organisation that registered the Sender ID and given to the Participating Aggregator handling the send. Check whose UEN any vendor-managed SSIR account sits under before you sign.
How do I let people unsubscribe from an SMS correctly?
Second Schedule paragraph 2(3)(a) requires a bulk marketing text to include a mobile telephone number to which the recipient may submit an unsubscribe request by text. An alphanumeric Sender ID is not a mobile number and generally cannot receive replies, so either register a long virtual number from the 8 or 9 series as a numeric Sender ID, or print a reply number in the body. The address must stay valid for at least 30 days, the statement must be clear, conspicuous and in English, and you must stop sending within 10 business days of the request.
How long does SSIR registration take?
SGNIC’s guidance is approximately 19 calendar days from account registration to the commencement of protection, provided documents are in order. Approved Sender IDs are conveyed to Participating Aggregators weekly, so check the portal reads “Live” with a date in the “Effective By” column before scheduling.
Where this leaves you
SMS is the most heavily gated marketing channel in Singapore and the least discussed. The gate is not the law — that is the same Spam Control Act and PDPA governing every other direct channel. The gate is a registry with a fee, a queue, a naming policy and a renewal date, and the failures we see are almost all administrative: a lapsed listing, an unregistered Sender ID in a booking system nobody audited, a case mismatch, an aggregator switch that broke the whitelist.
So the order of work reverses. Settle the Sender ID first: one name, registered to your own UEN, the most convincing variants blacklisted defensively, and the renewal date in a calendar somebody reads. Decide whether marketing runs from a separate LVN, because that resolves the unsubscribe conflict at source rather than in the copy. Then write the campaign, knowing you have about 80 usable characters.
If you would like your messaging channels reviewed alongside the rest of your acquisition, that is where our performance marketing engagements start.
Sources: SGNIC, “Overview of SMS Sender ID Registry (SSIR)”, “Rules of Registration” and “SMS Sender ID Registry” FAQs, sgnic.sg, accessed 5 September 2026; IMDA, “Enhanced measures against scam SMS”, media release, 25 January 2023; Spam Control Act 2007 (Singapore), ss 4A, 6, 11, 12, 13, 14 and the Second Schedule, Singapore Statutes Online, current version as at 5 September 2026; Personal Data Protection Act 2012 (Singapore), s43 and the Do Not Call provisions, Singapore Statutes Online. This is general information, not legal advice; rules and fees change — verify before relying on them.
