Bulk SMS in Hong Kong works best with a sender ID registered under OFCA's SMS Sender Registration Scheme, which shows a "#" prefix and reaches every network; unregistered alphanumeric IDs fail on China Mobile Hong Kong and numeric senders are overwritten. VoIP in Hong Kong is licensed by OFCA, and calls from outside Hong Kong must show a "+" before the number, even when it looks local.
Rules last checked: October 2026.
Bulk SMS in Hong Kong: the "#" registered sender scheme
OFCA, the Office of the Communications Authority, runs the SMS Sender Registration Scheme to fight SMS spoofing and phishing. Registered senders appear with a "#" prefix (for example #MyBrand), so recipients can tell a genuine company from an impostor. International senders can use registered "#" sender IDs through their provider since February 2024: the ID is registered first with OFCA, then with the provider.
| Sender type | Status in Hong Kong as of 2026 |
|---|---|
| Registered "#" alphanumeric | Recommended; reaches all networks |
| Unregistered alphanumeric | Works on most networks, but needs registration for China Mobile Hong Kong |
| Hong Kong long code | Supported, two-way capable |
| International long code or numeric sender | Not supported; overwritten |
| Short code | Supported on most networks, not on China Mobile Hong Kong |
Registration takes a few weeks. See sender ID registration by country and the similar Singapore SMS Sender ID Registry.
Unsolicited messages: UEMO and do-not-call registers
Commercial SMS is governed by the Unsolicited Electronic Messages Ordinance (UEMO), which OFCA enforces. Senders must identify themselves, include a working unsubscribe facility and honour unsubscribe requests, and must not send commercial messages to numbers on the Do-not-call Registers (which cover SMS, fax and pre-recorded voice messages) without consent. Personal data used for direct marketing also needs consent under the Personal Data (Privacy) Ordinance. Gambling, adult content, loans, political and religious content and controlled substances are commonly refused on A2P routes. See SMS opt-in and opt-out compliance.
Hong Kong mobile networks
The networks are CSL and 1O1O (HKT), China Mobile Hong Kong, SmarTone and 3 Hong Kong. Numbers have eight digits with no area code. Chinese text is sent in Unicode, so one SMS holds 70 characters. All SIM cards have needed real-name registration since 2023, which also limits anonymous SIM-based traffic. Test each network separately (how to test an SMS route).
VoIP in Hong Kong: licensing and numbering
VoIP is legal in Hong Kong for licensed providers. OFCA administers telecom licences under the Telecommunications Ordinance: network operators hold a Unified Carrier Licence, while many VoIP and resale providers hold a Services-Based Operator licence. Fixed numbers mostly start with 2 or 3, mobile numbers mostly with 5, 6 or 9, and freephone with 800. Mobile and fixed are priced separately on most rate decks (mobile termination rates).
CLI rules for calls to Hong Kong
Since 2015 OFCA has required operators to insert a "+" before the caller number on mobile phones for every incoming call that originates outside Hong Kong, even when the number imitates a local one. The prefix tells the called party the call comes from abroad. OFCA has repeatedly warned about pre-recorded scam calls that spoof government numbers, and advises the public to treat "+" calls with care.
For buyers: an international route cannot make a call look domestic in Hong Kong, so CLI-sensitive traffic (banks, delivery, call centers) needs a locally licensed provider. See CLI spoofing rules and CLI vs non-CLI routes.
What buyers ask for on Hong Kong routes
- Fixed and mobile rates, ASR, ACD and PDD.
- Whether CLI is passed and how it is presented.
- For SMS: "#" sender registration support, coverage on China Mobile Hong Kong and OTP latency.
Check coverage on the Hong Kong VoIP destination page and the Hong Kong SMS destination page, or read about our VoIP termination and A2P SMS routes. VoIPMatcher sources the route from its carriers and manages it; buyers and sellers never see each other. Request a Hong Kong voice route or request a Hong Kong SMS route.
Frequently asked questions
What does the # before an SMS sender name mean in Hong Kong?
It shows the sender is registered under OFCA's SMS Sender Registration Scheme. Only registered companies can send with a # prefix, so recipients can trust that #BankName really is the bank. Unregistered senders cannot use the prefix. OFCA advises the public to treat SMS from unregistered senders with more care.
How do I register an SMS sender ID in Hong Kong?
First register the sender ID under OFCA's SMS Sender Registration Scheme, then register it with your SMS provider so it can send with the # prefix. You need company documents proving your link to the name. A registered # sender reaches all Hong Kong networks, including China Mobile Hong Kong.
Why do calls to Hong Kong show a + before the number?
OFCA requires operators to add a + before the caller number on mobile phones for every call that comes from outside Hong Kong, even if the number looks local. It helps people spot overseas calls and spoofed local numbers. A call can only appear without the + if it really starts inside Hong Kong.
What is the Do-not-call Register in Hong Kong?
Under the Unsolicited Electronic Messages Ordinance, OFCA keeps Do-not-call Registers for SMS, fax and pre-recorded voice messages. Senders of commercial messages must not contact listed numbers without consent, must identify themselves and must provide a working unsubscribe facility. OFCA can investigate complaints and issue enforcement notices.
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