OFFICIAL · Hong Kong regulatory framework

OFCA in practice: CLI verification, Sender ID and the Do-Not-Originate list for SMS-A2P traffic into Hong Kong

The Office of the Communications Authority (OFCA) administers the Hong Kong numbering plan and Sender ID rules under the Telecommunications Ordinance (Cap. 106). Five mobile networks cover the territory: CSL (HKT), 3HK (Hutchison), SmarTone, China Mobile Hong Kong and China Unicom Hong Kong. 4notify routes through tier-1 direct interconnections with all five carriers, registers the alphanumeric Sender ID with each, and enforces the Do-Not-Originate list at the API edge — never via grey-route aggregation.

The five Hong Kong mobile operators

CSL (HKT)

Share: ~30% · P50: 2.6 s

Operated by HKT; broadest coverage including the cross-boundary footprint; preferred tier-1 route for regulated sectors.

3HK (Hutchison)

Share: ~22% · P50: 2.8 s

Hutchison Telecom; strong roaming proposition and high Sender ID acceptance.

SmarTone

Share: ~18% · P50: 2.9 s

Sun Hung Kai-backed; strong network quality in the Central business district.

China Mobile HK

Share: ~18% · P50: 3.0 s

Mainland-cross-boundary leader; large prepaid base.

China Unicom HK

Share: ~12% · P50: 3.1 s

Strong on enterprise IDD and international roaming.

OFCA numbering plan

+852 5xxx / 6xxx / 9xxx — MobileFive mobile carriers + MVNOs; OFCA requires a CLI verification chain.
+852 2xxx / 3xxx — Fixed / VoIPGeographic and voice-over-IP numbers for enterprises.
Short code (4-5 digits)Two-way SMS; brand registration with each carrier; dedicated or shared.
Alphanumeric Sender ID (≤11)Registered with each carrier; trade mark with demonstrable ownership required.

The five-step OFCA compliance chain

  1. 01

    OFCA filing + carrier contracts

    4notify is filed with OFCA as a messaging provider and holds Sender ID agreements with all five Hong Kong mobile carriers.

  2. 02

    Alphanumeric Sender ID registration

    Brands register their Sender ID with each carrier. Requirements: registered trade mark, sample message and use declaration. Activation: 5-10 business days.

  3. 03

    Do-Not-Originate verification

    Banks, government bureaux and emergency services may never be impersonated. 4notify mirrors the DNO list at the API edge every five minutes.

  4. 04

    Lawful basis enforcement (Cap. 486)

    For commercial messages the lawful basis under the Personal Data (Privacy) Ordinance is verified at envelope level; deliveries without permission are blocked at the API edge.

  5. 05

    STOP / UNSUBSCRIBE handling

    On every commercial message the keywords STOP and UNSUBSCRIBE are processed within three days under Cap. 593 and reflected in the suppression list.

Frequently asked questions

Do I need a Hong Kong company to send SMS into Hong Kong?

4notify operates tier-1 interconnections from European infrastructure, but for Sender ID registration you need a trade mark with demonstrable ownership. We accompany the filings with CSL, 3HK, SmarTone, China Mobile HK and China Unicom HK.

What is the penalty for impersonating a reserved Sender ID?

Impersonating a Sender ID on the DNO list (banks, government, emergency services) may attract enforcement action by OFCA and civil liability for fraud. That is why 4notify verifies the list before every send.

How long does Sender ID activation take?

Typically 5-10 business days. CSL tends to be the fastest; 3HK, SmarTone, China Mobile HK and China Unicom HK can take 1-2 days more.

Start free

Full OFCA compliance. Sender ID in 5-10 business days. English-speaking support on weekdays.