Asia
SIP Trunk Singapore — +65 Termination & DID Numbers
Singapore displays a '+' in front of incoming overseas caller IDs so recipients can spot spoofed local numbers, which makes honest, valid CLIs essential. Numbers are eight digits with no area codes: fixed lines start with 6, mobiles with 8 or 9, and VoIP ranges with 3.
Overview
Routing calls to Singapore
Traffic to Singapore leaves our SBCs on more than one upstream carrier per prefix. If a leg toward Central Area or Jurong East starts returning 503s or long post-dial delay, the next attempt goes to another carrier automatically. Calls to Tampines, Woodlands and Changi follow the same failover logic.
Numbering in Singapore is managed by IMDA. We terminate to geographic, national, mobile and toll-free ranges and price each one separately on the rate sheet. There is no trunk prefix to strip: send 65 followed by the national number as written.
Outbound termination to Singapore starts as soon as your balance is topped up. Local DIDs are different: IMDA rules usually require address and identity documents, which our team collects and checks before activation.
What you get
What you get in Singapore
One account and one balance, with the same SBCs for termination and inbound numbers.
CLI route tier
Caller ID delivered end to end on +65 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, National, 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 +65 prefix is mapped to more than one carrier. Failed attempts move to the next one automatically.
Number formats
How to dial Singapore from your PBX
Send E.164 digits. The sample number below shows the format only.
| Format | Example | Notes |
|---|---|---|
| International (E.164) | +65 6123 4567 | How the number is written and stored. |
| Sent from your PBX | 6561234567 | E.164 digits with no plus, prefixed by your tech prefix if your account uses one. |
| With 00 exit code | 00 65 6123 4567 | Accepted on the trunk. We normalise it to E.164. |
| National format | 6123 4567 | Dialled inside Singapore. There is no trunk prefix. |
Compliance
Singapore rules to know
What applies before your first call or your first DID goes live.
Compliance box
- Regulator
- IMDA
- 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 Singapore routes
- 01
APAC headquarters in Singapore running regional support on local numbers
- 02
Fintech and crypto firms verifying customers by voice
- 03
1800 toll-free lines for regional customer service
Setup
Start calling Singapore 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 +65
Send 65 + 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
Singapore SIP trunk questions
Why do calls from abroad show a '+' in Singapore?
Singapore's operators prefix incoming overseas caller IDs with '+' so recipients can recognise calls from outside the country.
What are 3xxx numbers?
Numbers in the 3 range are used for VoIP services.
Who regulates Singapore telecoms?
The IMDA (Infocomm Media Development Authority).
Do Singapore DIDs need documents?
Usually: a UEN company registration or identity documents.
