---
title: "Bulk SMS in Hong Kong: OFCA, # Sender ID, UEMO and PDPO"
description: "Bulk SMS Hong Kong guide: OFCA's SMS Sender Registration Scheme and # prefix, UEMO and PDPO direct marketing rules, operators, Chinese SMS length."
canonical: "https://omnichannels.ai/blog/bulk-sms-hong-kong-guide/"
language: "en"
updated: "2026-11-06"
publisher: "BroadNet Technologies"
brand: "OmniChannels.ai"
category: "sms"
primaryQuery: "bulk sms hong kong"
keywords: ["bulk sms hong kong", "hong kong sms sender id", "ofca sms sender registration scheme", "hash prefix sender id hong kong", "unsolicited electronic messages ordinance sms", "pdpo direct marketing sms", "香港 群发短信"]
published: "2026-11-06"
author: "OmniChannels.ai Editorial Team"
reviewer: "BroadNet Messaging Solutions Team"
readingMinutes: 10
answer: "To send bulk SMS in Hong Kong, use a provider with routes to CSL, China Mobile Hong Kong, 3 Hong Kong and SmarTone, and decide whether to register your sender ID under OFCA's SMS Sender Registration Scheme, which gives registered senders a \"#\" prefix. Follow the Unsolicited Electronic Messages Ordinance (identify yourself, offer an unsubscribe route) and the PDPO direct marketing rules. Traditional Chinese text is Unicode, so one message holds 70 characters."
takeaways: ["OFCA's SMS Sender Registration Scheme has run since 28 December 2023: registered organisations send under sender IDs that begin with #, and OFCA said networks would block # IDs that do not come from a registered sender. Our regulation data lists the scheme as voluntary for the sender.", "The Unsolicited Electronic Messages Ordinance (Cap. 593) requires commercial electronic messages to carry accurate sender information and an unsubscribe facility, and it sets up do-not-call registers that include short messages.", "Using personal data for direct marketing is separately governed by the Personal Data (Privacy) Ordinance: the PCPD describes a notice-and-consent step before first use (s.35C), an opt-out statement (s.35F) and a duty to stop on request without charge (s.35G).", "Four mobile networks appear in our coverage data, all with direct routes: CSL Mobile (454-00), China Mobile HK (454-12), 3HK (454-04) and SmarTone (454-06).", "A message containing Chinese characters is Unicode: SmarTone states 70 Chinese characters per message, and concatenated Unicode parts carry 67. English-only text stays at 160 (153 per part)."]
faq: 
  - q: "Is bulk SMS legal in Hong Kong?"
    a: "Yes. Businesses send OTPs, alerts and marketing SMS, provided they follow the Unsolicited Electronic Messages Ordinance, the personal data rules for direct marketing and the operators' route policies. No single law is called a bulk SMS law. Keep consent records, identify the sender, give a working unsubscribe route and take advice from Hong Kong counsel on marketing campaigns."
  - q: "What is the # sender ID in Hong Kong?"
    a: "It is the prefix OFCA's SMS Sender Registration Scheme gives to registered senders, so that recipients can tell a message comes from a verified organisation. Per OFCA's launch announcement, networks block messages that use a # sender ID without being sent by a registered sender. Unregistered senders keep using sender IDs without the #."
  - q: "Do I have to register under the SMS Sender Registration Scheme?"
    a: "Our regulation data describes the scheme as voluntary, and OFCA says organisations apply to it directly. In practice a # ID helps recipients trust your message, and some sectors have been encouraged to join. Ask your provider which of your SMS traffic is covered, because messages that invite a phone reply are outside the scheme."
  - q: "Do I need consent to send promotional SMS in Hong Kong?"
    a: "Plan on a documented opt-in. The Ordinance bars messages to numbers on a do-not-call register unless the user consents, and the PDPO requires you to inform people and obtain their consent before using their personal data for direct marketing. Our regulation data calls for verifiable opt-in. Keep wording, timestamp, channel and number."
  - q: "How long is a Chinese SMS in Hong Kong?"
    a: "Chinese characters use Unicode, so a single SMS holds 70 characters, including spaces, digits and punctuation. Longer text is split into parts of 67 characters each. A message in English letters and digits only fits the GSM 7-bit alphabet at 160 characters. Check final copy in a character counter before you send."
  - q: "How long does sender ID registration take in Hong Kong?"
    a: "Our published position is free-form: the OFCA scheme is voluntary and there is no fixed lead time. Review times depend on OFCA and on your documents. Build buffer into your launch plan, test delivery on all four networks, and let us prepare and file the application with you."
sources: 
  - title: "SMS Sender Registration Scheme, OFCA"
    url: "https://www.ofca.gov.hk/en/consumer_focus/guide/hot_topics/ssrs/index.html"
  - title: "SMS Sender Registration Scheme to be launched on December 28, HKSAR Government press release"
    url: "https://www.info.gov.hk/gia/general/202312/20/P2023122000391p.htm"
  - title: "Unsolicited Electronic Messages Ordinance (Cap. 593), e-Legislation"
    url: "https://www.elegislation.gov.hk/hk/cap593"
  - title: "Personal Data (Privacy) Ordinance and direct marketing, PCPD"
    url: "https://www.pcpd.org.hk/"
  - title: "3GPP TS 23.038: Alphabets and language-specific information"
    url: "https://www.3gpp.org/dynareport/23038.htm"
---

# Bulk SMS in Hong Kong: OFCA, # Sender ID, UEMO and PDPO

Canonical: https://omnichannels.ai/blog/bulk-sms-hong-kong-guide/
Language: en
Publisher: OmniChannels.ai by BroadNet Technologies

This guide is for retail, banking, travel and service teams that want to send business SMS to mobile numbers in Hong Kong: OTPs, booking alerts, reminders and promotions. It explains who regulates what, how OFCA's "#" sender ID scheme works, what the Unsolicited Electronic Messages Ordinance and the Personal Data (Privacy) Ordinance mean for you, and how Traditional Chinese text changes message length. It is a practical overview, not legal advice; confirm requirements with Hong Kong counsel and the operators before launch.

## What rules apply to bulk SMS in Hong Kong?

Four layers apply: telecom regulation by OFCA, the Unsolicited Electronic Messages Ordinance (UEMO), the Personal Data (Privacy) Ordinance (PDPO), and each operator's route policy. Together they cover who you are, whether you may contact someone, and how their data is used.

| Layer | What it covers | Where to check |
|---|---|---|
| OFCA (Office of the Communications Authority) | Telecom regulation; the SMS Sender Registration Scheme | [ofca.gov.hk](https://www.ofca.gov.hk/) |
| UEMO, Cap. 593 | Commercial electronic messages: sender information, unsubscribe, do-not-call registers | [e-Legislation](https://www.elegislation.gov.hk/hk/cap593) |
| PDPO, Cap. 486 | Use of personal data in direct marketing: notice, consent, opt-out | [pcpd.org.hk](https://www.pcpd.org.hk/) |
| Operators (CSL, China Mobile HK, 3HK, SmarTone) | Route set-up, filtering, sender ID handling | Your provider confirms at onboarding |

Our regulation data lists OFCA as the regulator and records that opt-in must be verifiable. It also records that the OFCA sender scheme is voluntary, so the rule that matters on launch day is often the one your route and your own consent records enforce.

## What is the OFCA SMS Sender Registration Scheme and the # prefix?

It is a scheme, live since 28 December 2023, under which verified organisations register their sender IDs with OFCA and send under IDs that start with "#". Recipients can then tell the message comes from a registered sender. OFCA's launch announcement said telecom networks would block SMS that use a "#" sender ID but do not come from a registered sender.

Key points from OFCA's own pages:

- **Who can join.** The first phase covered the telecom sector, and OFCA now says the scheme is open for application by all sectors. Organisations apply to OFCA and registered IDs appear in a public SMS Sender Registry.
- **What it excludes.** It does not cover messages that expect the recipient to reply by phone, which usually carry numeric-only sender IDs, and it applies to Hong Kong mobile numbers used in Hong Kong.
- **Subscribers do nothing.** Mobile providers offer the service free; customers need not install apps or change settings.
- **Unregistered senders.** They keep using sender IDs without the "#". Those messages are not identity-verified, and OFCA advises caution with them.

Our regulation data adds that the scheme is voluntary for the sender and that unregistered IDs are delivered without the "#". Read together: you can send without registering, but a "#" ID tells your customers that the message is genuine, which matters in a market where impersonation scams drove the scheme. Definitions are in [sender ID](/glossary/sender-id/) and [alphanumeric sender ID](/glossary/alphanumeric-sender-id/).

## How do you register a sender ID in Hong Kong?

You prepare your company documents, choose names that match your brand, apply to OFCA's scheme (your provider can prepare the filing with you), and then test delivery on every network. Our data records no fixed lead time because the scheme is voluntary, so build in buffer.

| Step | What to do |
|---|---|
| 1. Classify | Separate transactional traffic (OTP, alerts) from promotional traffic, and decide which sender IDs you need |
| 2. Choose names | Use your registered business or brand name; avoid names that imitate banks, operators or government bodies |
| 3. Prepare documents | Business registration evidence and an authorisation letter naming the IDs and your provider |
| 4. Apply | File with OFCA's scheme; track the result in the public registry |
| 5. Test | Send an OTP and a promotion to CSL, China Mobile HK, 3HK and SmarTone handsets |

Our [sender ID letter generator](/tools/sender-id-letter-generator/) drafts the authorisation letter, the [sender ID checker](/tools/sender-id-checker/) and the [Hong Kong sender ID page](/sender-id/hong-kong/) show the current position, and [registrations](/services/registrations/) explains how we prepare and file with you. Approval decisions stay with OFCA and the operators. For formats in general, see [SMS sender ID types explained](/blog/sms-sender-id-types-explained/).

## What does the Unsolicited Electronic Messages Ordinance require?

The UEMO requires commercial electronic messages, including SMS, to carry accurate sender information and an unsubscribe facility, and to stop when people unsubscribe. It also creates do-not-call registers, one of which covers short messages, and bars sending to a registered number without the user's consent.

HKSAR Government material from the Ordinance's launch (effective December 2007) describes these duties, and the Telecommunications Authority can issue enforcement notices to senders that break them. Treat the e-Legislation text as the authority on exact periods and penalties, and check it before you finalise processes. Practical consequences:

1. **Say who is sending** at the start of every promotional SMS.
2. **Include a working unsubscribe route** such as a reply keyword or a link, and test it.
3. **Apply opt-outs everywhere**, across campaigns, sender IDs and channels, using one suppression list.
4. **Screen lists against the do-not-call register** before promotional sends, unless you hold the user's consent.
5. **Keep records** so you can answer a complaint.

Transactional messages that complete a transaction the customer asked for sit differently from promotions, but do not hide an offer inside an OTP. See [opt-out](/glossary/opt-out/) and [DND registry](/glossary/dnd-registry/).

## What does the PDPO add for SMS marketing?

If you use personal data, such as a phone number tied to a name, for direct marketing, the PDPO adds its own steps. The PCPD describes three: inform the individual and obtain consent before first use (s.35C), state the right to opt out without charge when you first use the data (s.35F), and stop using the data when asked, free of charge (s.35G). The PCPD cites a maximum penalty of a fine of HK$500,000 and three years' imprisonment for failing to comply with a cease-use request under s.35G(4).

In practice this means your sign-up wording should state that the number will be used for promotional SMS, what kinds of offers, and how to opt out. Our [opt-in consent generator](/tools/opt-in-consent-generator/) drafts wording, and the guide to [opt-in consent across channels](/blog/opt-in-consent-multichannel-campaigns/) shows how to record it. Do not buy lists: a purchased number has no consent trail.

## Which operators carry SMS in Hong Kong?

Four mobile networks appear in our coverage data, each with a direct route.

| Operator | MCC-MNC |
|---|---|
| CSL Mobile | 454-00 |
| China Mobile HK | 454-12 |
| 3HK | 454-04 |
| SmarTone | 454-06 |

Read delivery reports per network, not as one blended figure; a healthy total can hide a weak network. Our guide to [improving SMS delivery rates](/blog/sms-not-delivered-improve-delivery-rate/) shows how to diagnose it.

## How should you separate OTP and promotional traffic?

Keep OTPs, booking alerts and other service messages on their own sender ID and route, and promotions on another. A promotion inside an OTP puts login codes at risk if the promotional route is filtered or a recipient complains.

| Traffic | Example | Practice |
|---|---|---|
| Transactional | OTP, payment confirmation, delivery alert | No offer inside; own sender ID; any hour |
| Promotional | Sale, new menu, loyalty offer | Consented numbers; do-not-call screening; unsubscribe route; daytime schedule |
| Mixed | "Your table is booked. Get 10% off next time" | Avoid; the offer makes it promotional |

For OTP design see the [OTP authentication messages guide](/blog/otp-authentication-messages-guide/).

## How does Traditional Chinese affect SMS length?

Any Chinese character moves the whole message to Unicode, where one message holds 70 characters (67 per part when split). SmarTone states the same limit on its site: 70 Chinese characters or 160 English characters, including spaces, digits and punctuation. English letters and digits alone fit GSM 7-bit at 160 (153 per part). See [GSM-7](/glossary/gsm-7/), [Unicode SMS](/glossary/unicode-sms/) and [concatenated SMS](/glossary/concatenated-sms/).

| Encoding | Single message | Per part when concatenated |
|---|---|---|
| GSM 7-bit | 160 characters | 153 |
| Unicode (UCS-2) | 70 characters | 67 |

These examples were counted against the limits (full-width punctuation counts as one character each):

| Message | Encoding | Characters | Parts |
|---|---|---|---|
| `【晨光茶餐廳】您的驗證碼是482913，請勿向任何人透露。` | Unicode | 29 | 1 |
| `【晨光茶餐廳】訂座確認：本週六晚上7時，4位。如需更改請致電2123 4567。` | Unicode | 40 | 1 |
| `Morning Light: your code is 482913. Never share it with anyone.` | GSM-7 | 63 | 1 |
| `【晨光茶餐廳】本週六全單85折，掃碼訂座：morninglight.example/b 退訂請回覆STOP，歡迎帶同家人朋友一起來品嚐我們的新菜單。` | Unicode | 74 | 2 |

The English row shows why bilingual brands often send the English version of an OTP and keep Chinese copy for campaigns. A message that mixes both is Unicode throughout. Check final copy in the [SMS character counter](/tools/sms-character-counter/) and read [SMS character limits and Unicode](/blog/sms-character-limits-unicode-arabic/).

## When should you send?

We have not found a regulator-published time-of-day window for promotional SMS in Hong Kong, and our regulation data records none. Agree sending hours with your provider, send promotions in local daytime (Hong Kong Time, UTC+8) and avoid late evenings. OTPs and alerts can go at any hour. The [send time planner](/tools/send-time-planner/) helps schedule campaigns, and [SMS marketing rules by country](/blog/sms-marketing-rules-by-country/) compares hours across markets.

## A worked example: a Kowloon restaurant group

"Morning Light" (synthetic) runs 12 restaurants and wants booking reminders, a loyalty OTP and a weekly offer.

- It registers one "#" sender ID for service messages and one for offers, after checking both with OFCA's scheme and testing on all four networks.
- It collects consent in the app and at the till, stating that numbers will receive offers by SMS and how to stop, and stores the wording, timestamp and number.
- Booking reminders and OTPs are short and carry no offer.
- Offers are screened against the suppression list and the do-not-call register, scheduled for local daytime, and include a one-step unsubscribe.
- Opt-outs from SMS also suppress WhatsApp and email.

## What are the common mistakes?

- **Using a # look-alike.** Sending under a "#" ID without registration is a block risk.
- **Assuming reply-by-phone messages are covered by the scheme.** They are excluded.
- **No unsubscribe route.** The UEMO expects one.
- **Treating the scheme as legal consent.** A registered ID proves who you are, not that the recipient agreed.
- **Mixing OTP and promotion on one sender ID.**
- **Ignoring encoding.** One Chinese character in an English message turns it into a 70-character message.

## How OmniChannels.ai helps

OmniChannels.ai is powered by BroadNet, which has direct routes to CSL, China Mobile HK, 3HK and SmarTone in our coverage data. We prepare and file sender ID registration with you, support Traditional Chinese and English content, and give you per-network delivery reports, with SMPP 3.4 for high volume. For indicative list prices, see the [Hong Kong SMS pricing page](/sms-pricing/hong-kong/), then [book a demo](/demo/). Small team? Our [SMS marketing guide for small businesses](/blog/sms-marketing-small-business-guide/) covers the basics.