Asia
SIP Trunk Hong Kong — +852 Termination & DID Numbers
Hong Kong introduced real-name registration for all SIM cards in 2023, and OFCA has steadily tightened its anti-scam rules on calls. Numbers are eight digits with no area codes: fixed lines start with 2 or 3, and mobiles with 5, 6 or 9.
Overview
Routing calls to Hong Kong
Whether you are calling a desk phone in Hong Kong Island or a mobile in Tsuen Wan, Sha Tin and Tuen Mun, the call is routed by the longest matching +852 prefix and sent to the best-performing carrier for that range. When a carrier fails, the next one takes over, and the CDR shows exactly which leg carried the call.
OFCA sets the Hong Kong numbering plan, and our prefix tables follow it closely. Supported number types: geographic, mobile and toll-free. There is no trunk prefix to strip: send 852 followed by the national number as written.
For inbound numbers in Hong Kong, plan on paperwork: proof of address and company or identity documents are usually required before a DID goes live. Termination needs no documents beyond normal account checks.
What you get
What you get in Hong Kong
One account and one balance, with the same SBCs for termination and inbound numbers.
CLI route tier
Caller ID delivered end to end on +852 calls. Use it for sales, support and any traffic where answer rates matter.Non-CLI route tier
A lower-cost tier where caller ID delivery is not guaranteed. Suitable for internal or transactional traffic that does not depend on the CLI.Number types
Geographic, Mobile, Toll-free. DID availability varies by range and city.Codecs
G.711a/u and G.729 on every route, G.722 and Opus where the far end supports them. T.38 for fax.Channels on demand
Concurrent call limits are set per account and raised as your traffic grows. No fixed channel bundles.Multi-carrier failover
Every +852 prefix is mapped to more than one carrier. Failed attempts move to the next one automatically.
Number formats
How to dial Hong Kong from your PBX
Send E.164 digits. The sample number below shows the format only.
| Format | Example | Notes |
|---|---|---|
| International (E.164) | +852 2123 4567 | How the number is written and stored. |
| Sent from your PBX | 85221234567 | E.164 digits with no plus, prefixed by your tech prefix if your account uses one. |
| With 00 exit code | 00 852 2123 4567 | Accepted on the trunk. We normalise it to E.164. |
| National format | 2123 4567 | Dialled inside Hong Kong. There is no trunk prefix. |
Compliance
Hong Kong rules to know
What applies before your first call or your first DID goes live.
Compliance box
- Regulator
- OFCA
- Caller ID
- A valid CLI that you are entitled to use is required on CLI routes. Spoofed or unallocated numbers are blocked.
- DID KYC
- Usually required
Rules change — our team confirms current requirements before activation.
Use cases
Who uses Hong Kong routes
- 01
Financial services firms in Central with local 2xxx numbers
- 02
Trading companies calling mainland China and Southeast Asia
- 03
800 toll-free lines for retail and travel
Setup
Start calling Hong Kong in 3 steps
- 01
Top up $200
Open a prepaid account and add balance by USDT (TRC20), BTC or card. - 02
Add your trunk
Whitelist your PBX IP or create digest credentials, then point your outbound route at our SBC. - 03
Dial +852
Send 852 + national number in E.164 and check the CDR for your first test call.
Further reading: What Is a SIP Trunk? A Plain-English Guide for 2026
FAQ
Hong Kong SIP trunk questions
Does Hong Kong have area codes?
No. All numbers are 8 digits. Send 852 + 8 digits.
Who regulates Hong Kong telecoms?
OFCA (Office of the Communications Authority).
Do Hong Kong DIDs need documents?
Usually: a Business Registration certificate or identity documents.
How do I recognise Hong Kong mobiles?
They start with 5, 6 or 9.
