Whose number starts with 0403?
The 0403 mobile prefix appears in the ACMA register as held by OPTUS MOBILE PTY LIMITED, which holds every one of the window's 1m allocated numbers. The earliest allocation in 0403 is dated 24 May 1999 (to SINGTEL OPTUS PTY LIMITED, since transferred to OPTUS MOBILE PTY LIMITED), the most recent 9 March 2000.
Source: ACMA register, data as of 16/10/2026
The story of 0403
0403 completes the 1999–2000 Optus trio: Singtel Optus took the window in three arcs, the earliest in May 1999, and the register records the same 30 January 2003 transfer to Optus Mobile that applies to 0401 and 0402. Unlike 0411–0413 there was no analogue predecessor — 0403 was born as a GSM range.
The 0403 ranges in the ACMA register
The 0403 window is covered by 3 allocations with a combined capacity of about 1m numbers, in the hands of 1 holder. Every range have changed hands since allocation: the register still names SINGTEL OPTUS PTY LIMITED as original allocatee, with the latest transfer recorded on 30 January 2003.
| Range | Numbers | Original allocatee | Current holder | Allocated | Transferred |
|---|---|---|---|---|---|
| 0403000000–0403199999 | 200,000 | SINGTEL OPTUS PTY LIMITED | OPTUS MOBILE PTY LIMITED | 24/05/1999 | 30/01/2003 |
| 0403200000–0403399999 | 200,000 | SINGTEL OPTUS PTY LIMITED | OPTUS MOBILE PTY LIMITED | 20/09/1999 | 30/01/2003 |
| 0403400000–0403999999 | 600,000 | SINGTEL OPTUS PTY LIMITED | OPTUS MOBILE PTY LIMITED | 09/03/2000 | 30/01/2003 |
- 0403000000–0403199999 (200,000 numbers) was allocated on 24 May 1999 to SINGTEL OPTUS PTY LIMITED and transferred on 30 January 2003 to OPTUS MOBILE PTY LIMITED.
- 0403200000–0403399999 (200,000 numbers) was allocated on 20 September 1999 to SINGTEL OPTUS PTY LIMITED and transferred on 30 January 2003 to OPTUS MOBILE PTY LIMITED.
- 0403400000–0403999999 (600,000 numbers) was allocated on 9 March 2000 to SINGTEL OPTUS PTY LIMITED and transferred on 30 January 2003 to OPTUS MOBILE PTY LIMITED.
Optus Mobile in 0403 and nationally
OPTUS MOBILE PTY LIMITED holds 1m numbers in 0403 — the whole window — which is a small slice of its 29.4m mobile numbers nationally, or about 34% of every allocated Australian mobile number. The register places Optus Mobile in 24 different 04xx prefixes, including 2 of the other nine in the 0400–0409 decade (0401, 0402).
| Holder | Numbers in 0403 | Share of 0403 | Share of all 04 numbers | Prefixes held |
|---|---|---|---|---|
| OPTUS MOBILE PTY LIMITED | 1m | 100% | 34% | 24 |
The other prefixes in the 0400–0409 decade
Held by Telstra, Optus Mobile and Vodafone Australia: 0400, 0401, 0402, 0404, 0405, 0406, 0407, 0408, 0409. The decade's oldest allocation is in 0409 (10 March 1998, Telstra), its youngest in 0404 (25 August 2005, Vodafone Australia). Every allocated prefix in the decade has a single holder.
What does a call from a 0403 number mean?
Standard mobile rates. A 0403 number tells you only that the range holder of record is Optus Mobile; after porting the SIM can sit on any Australian network.
What people check and report about 0403 numbers
From searches typed into this site's lookup form since 3 September 2026, and the verdicts and moderated reports visitors left. A check usually follows a missed call.
No published reports for this prefix yet.
Had a call from a 0403 number?
No clear pattern in reports on these numbers yet. If a call worried you:
- Call back on a number you trust
If a caller says they're your bank, the ATO, Services Australia, a courier or your telco, hang up and ring the organisation on the number from its website or your statement, never the number that called you. Caller ID can be faked.
- Report the call to Scamwatch
The National Anti-Scam Centre uses Scamwatch reports to warn others and to get scam numbers blocked. Note the number, the time and what the caller claimed to be. If anyone is in danger, call 000.
- Register on the Do Not Call Register
Registering landlines and mobiles is free and stops most telemarketing calls within 30 days. Charities, political parties, surveys and scammers aren't covered.
- Forward spam texts to 0429 999 888
The ACMA collects unsolicited commercial texts forwarded to 0429 999 888 (standard message charges apply). Don't edit the message first. Scam texts that impersonate a bank, toll road or delivery company go to Scamwatch instead.
Nationally, Scamwatch recorded $72.5 million lost to scams that started with a phone call in 2025 (down from $107.2 million), with a median loss of $3,800 per report that lost money, and phone-call scam reports are 73.7% below their 2021 level. Telcos blocked 109.3 million scam calls and 45.2 million scam texts in January to March 2026. Sources: Targeting scams 2025 (National Anti-Scam Centre); ACMA quarterly report, Jan–Mar 2026.
0403 numbers: questions and answers
Which network does a 0403 number belong to?
The ACMA register lists Optus Mobile as the holder of every allocated number in 0403 (1m numbers). Mobile numbers can be moved to another network, so the caller may now be with a different provider.
When was 0403 first allocated?
The earliest 0403 range in the register is dated 24 May 1999, to Singtel Optus; the most recent 9 March 2000. The window is covered by 3 register ranges.
How big is Optus Mobile's share of Australian mobile numbers?
Across the whole 04 range, Optus Mobile holds about 34% of allocated mobile numbers, spread over 24 of the 04xx prefixes.
How often are 0403 numbers checked?
People have checked 21 different 0403 numbers 22 times on this site since 3 September 2026, with no verdicts or reports yet.
How do I report a scam call or text from a 0403 number?
Report scam calls and texts to Scamwatch. Forward unsolicited commercial texts to the ACMA on 0429 999 888, and block the number from your phone's recent calls or messages. If you lost money, call your bank first, then report it through ReportCyber.
Check a 0403 number
Range data is not personal data and the number on your screen can be spoofed. Scam calls: Scamwatch. Guides: Who called me from this number?, Which carrier owns which mobile prefix?