Whose number starts with 0400?
The 0400 mobile prefix appears in the ACMA register as held by TELSTRA LIMITED. Important: the register names the range holder; after number porting an individual 0400 number can operate on any other network today.
Source: ACMA register, data as of 31/08/2026
The 0400 range carries one of the stranger stories in Australian numbering: the register still names One.Tel — the telco that collapsed spectacularly in 2001 — as the original allocatee, with Telstra recorded as the latest holder of the arcs. Numbers here have changed corporate hands without their owners ever noticing.
The 0400 ranges in the ACMA register
The 0400 window is covered by 3 allocations with a combined capacity of about 1m numbers, in the hands of 1 holder.
| Range start | Numbers | Held by |
|---|---|---|
| 0400000000… | 300,000 | TELSTRA LIMITED |
| 0400300000… | 500,000 | TELSTRA LIMITED |
| 0400800000… | 200,000 | TELSTRA LIMITED |
What does a call from a 0400 number mean?
A 0400 number is an ordinary mobile at ordinary rates. The register names the range holder, not the person calling — and with number porting the SIM may live on a different network entirely.
No published reports for this prefix yet.
Check a 0400 number
Worth knowing
- The prefix tells you where a line was issued, not who is calling: range data is not personal data, and the number on your screen can be spoofed.
- Report scam calls to Scamwatch; unwanted telemarketing can be reported to the ACMA once your number has been on the Do Not Call Register for 30 days.
- Learn more: Who called me from this number? and Which carrier owns which mobile prefix?