Onslow: landline numbers and carriers

Onslow is one of the town-level numbering areas the ACMA register uses under area code 08 (SA, WA & NT). The register lists 35 number blocks for it with about 40,000 allocated numbers, held by 19 carriers and spread over the 0891… and 0851… dialling prefixes. That makes Onslow the 61st largest of 640 numbering areas under 08 by block count, with 0.14% of the area code's allocated numbers. A landline that calls you from one of these blocks was issued for the Onslow area — though the line may since have been ported, and caller ID can be spoofed.

Source: ACMA register, data as of 15/10/2026

35blocks in the register
19carriers with allocations
40,000allocated numbers
1991first allocation

Where Onslow is

State or territory
Western Australia
Council area
Ashburton
Local time
— AWST, UTC+8, no daylight saving
Number format
08 91xx xxxx; from overseas +61 8 91xx xxxx
Nearest numbering areas
Exmouth (112 km), Pannawonica (122 km), Dampier (197 km), Karratha (204 km), Millstream (Ext) (237 km)

Locality, council and state: ABS ASGS Edition 3 (CC BY 4.0). Distances are straight-line between localities.

Map of the Onslow numbering area in Western Australia and the nearest other numbering areas
Shaded: Ashburton council area. The ACMA doesn't publish numbering-area boundaries, so the dot marks the Onslow locality rather than an exact outline; the inset shows where the map sits in Australia. Boundaries: ABS (CC BY 4.0).

How Onslow was numbered

The oldest block in Onslow was allocated on 30 June 1991 and is held today by TELSTRA LIMITED; the newest on 19 August 2026 to SYMBIO NETWORKS PTY LTD. Most of the area's blocks — 7 of 35 — date from 2015–2019, but allocations here span 35 years. 31 of the blocks are the standard 1,000-number size. 6 allocated blocks have changed hands since they were first issued: the register still names AAPT LIMITED, ENGIN PTY LIMITED, GOTALK LIMITED, IPTEL PTY LIMITED, IVOX PTY LTD and TWILIO AUSTRALIA PTY LTD as original allocatees of blocks now held by other carriers.

PeriodBlocks allocated
1990–19944
2000–20043
2005–20096
2010–20145
2015–20197
2020–20246
2025–20294

The carriers in Onslow

Onslow is spread across carriers: TELSTRA LIMITED leads with 25% of allocated numbers ahead of SYMBIO NETWORKS PTY LTD on 15%, and 19 carriers hold blocks in total. TELSTRA LIMITED has the longest tenure, with a block dated 30/06/1991; SYMBIO NETWORKS PTY LTD received the newest, on 19/08/2026. SYMBIO NETWORKS PTY LTD (3), SOUL PATTINSON TELECOMMUNICATIONS PTY LIMITED (1) and PRIMUS TELECOMMUNICATIONS PTY LIMITED (1) hold blocks originally allocated to another carrier.

CarrierBlocksNumbersShareFirst blockLatest block
TELSTRA LIMITED810,00025%30/06/199106/05/2016
SYMBIO NETWORKS PTY LTD66,00015%29/06/200519/08/2026
SOUL PATTINSON TELECOMMUNICATIONS PTY LIMITED24,00010%30/03/200014/07/2016
PRIMUS TELECOMMUNICATIONS PTY LIMITED33,0007.5%24/12/200403/02/2012
NETSIP PTY LTD22,0005%14/02/201826/10/2021
OPTUS MOBILE PTY LIMITED12,0005%02/12/200802/12/2008
ADARGA PTY LTD11,0002.5%16/09/202516/09/2025
C2A INTERNET.COM.AU PTY. LTD.11,0002.5%13/07/202313/07/2023
CHECK TECHNOLOGY GROUP PTY LTD11,0002.5%31/01/202231/01/2022
CHIME COMMUNICATIONS PTY LTD11,0002.5%14/07/200414/07/2004
GENNEXT ENTERPRISES PTY LTD11,0002.5%03/10/201903/10/2019
LMGPS LTD11,0002.5%23/11/202323/11/2023
NETERA PTY LTD11,0002.5%24/10/202524/10/2025
OPTUS NETWORKS PTY LIMITED11,0002.5%16/06/200516/06/2005
PIPE NETWORKS PTY LIMITED11,0002.5%24/09/201224/09/2012
PIVOTEL SATELLITE PTY LIMITED11,0002.5%16/04/202516/04/2025
THE TRUSTEE FOR READING FAMILY TRUST11,0002.5%21/10/201921/10/2019
VIRTUTEL PTY LTD11,0002.5%20/12/201520/12/2015
WHY PAY MORE 4 LESS PTY LTD11,0002.5%10/05/201810/05/2018

Number blocks registered for Onslow

Every registered block for this area is allocated to a carrier. All 35 blocks, ascending:

Block startNumbersOriginal allocateeCurrent holderAllocatedTransferred
0851017000…1,000=VIRTUTEL PTY LTD20/12/2015—
0851046000…1,000=SOUL PATTINSON TELECOMMUNICATIONS PTY LIMITED14/07/2016—
0851075000…1,000=NETSIP PTY LTD14/02/2018—
0851104000…1,000=ADARGA PTY LTD16/09/2025—
0851133000…1,000=THE TRUSTEE FOR READING FAMILY TRUST21/10/2019—
0851191000…1,000=WHY PAY MORE 4 LESS PTY LTD10/05/2018—
0851214000…1,000=NETSIP PTY LTD26/10/2021—
0851215000…1,000=SYMBIO NETWORKS PTY LTD19/06/2020—
0851242000…1,000TWILIO AUSTRALIA PTY LTDSYMBIO NETWORKS PTY LTD24/09/202015/10/2020
0851251000…1,000=GENNEXT ENTERPRISES PTY LTD03/10/2019—
0851305000…1,000=CHECK TECHNOLOGY GROUP PTY LTD31/01/2022—
0851336000…1,000=C2A INTERNET.COM.AU PTY. LTD.13/07/2023—
0851365000…1,000=LMGPS LTD23/11/2023—
0851395000…1,000=PIVOTEL SATELLITE PTY LIMITED16/04/2025—
0851424000…1,000=NETERA PTY LTD24/10/2025—
0851454000…1,000=SYMBIO NETWORKS PTY LTD19/08/2026—
0891060000…3,000IPTEL PTY LIMITEDSOUL PATTINSON TELECOMMUNICATIONS PTY LIMITED30/03/200001/12/2004
0891112000…1,000ENGIN PTY LIMITEDPRIMUS TELECOMMUNICATIONS PTY LIMITED24/12/200411/08/2015
0891169000…1,000=PRIMUS TELECOMMUNICATIONS PTY LIMITED26/05/2005—
0891200000…1,000=OPTUS NETWORKS PTY LIMITED16/06/2005—
0891228000…1,000GOTALK LIMITEDSYMBIO NETWORKS PTY LTD29/06/200527/08/2013
0891291000…1,000=SYMBIO NETWORKS PTY LTD24/04/2014—
0891338000…1,000=PRIMUS TELECOMMUNICATIONS PTY LIMITED03/02/2012—
0891392000…1,000IVOX PTY LTDSYMBIO NETWORKS PTY LTD18/06/201216/06/2014
0891411000…2,000=OPTUS MOBILE PTY LIMITED02/12/2008—
0891491000…1,000AAPT LIMITEDPIPE NETWORKS PTY LIMITED24/09/201224/03/2026
0891532000…1,000=TELSTRA LIMITED11/04/2014—
0891537000…1,000=TELSTRA LIMITED06/05/2016—
0891599000…1,000=TELSTRA LIMITED30/06/1991—
0891812000…2,000=TELSTRA LIMITED02/09/2009—
0891816000…1,000=TELSTRA LIMITED04/09/2009—
0891843000…1,000=TELSTRA LIMITED30/06/1991—
0891846000…2,000=TELSTRA LIMITED30/06/1991—
0891849000…1,000=TELSTRA LIMITED30/06/1991—
0891977000…1,000=CHIME COMMUNICATIONS PTY LTD14/07/2004—

Numbering areas next to Onslow in the register

Immediately below and above Onslow's blocks in the 0891… and 0851… prefixes sit Leopold (Ext), Marble Bar, Millstream (Ext), Mitchell (Ext) (WA), Mount Bruce (Ext), Newman, Ord (Ext), Pannawonica, Paraburdoo, Port Hedland, Roebuck (Ext) and Sandfire (Ext).

Numbering areaFirst blockBlocksCarriers
Leopold (Ext)0851011000…3018
Marble Bar0851012000…2918
Millstream (Ext)0851013000…3218
Mitchell (Ext) (WA)0851014000…3018
Mount Bruce (Ext)0851015000…3118
Newman0851016000…4220
Ord (Ext)0851018000…3019
Pannawonica0851019000…3119
Paraburdoo0851020000…3319
Port Hedland0851021000…5020
Roebuck (Ext)0851022000…3119
Sandfire (Ext)0851023000…3319

Had a call from a Onslow number?

No clear pattern in reports on these numbers yet. If a call worried you:

  1. 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.

  2. 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.

    Report to Scamwatch ↗

  3. 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.

    Do Not Call Register ↗

  4. If you lost money or shared details

    Call your bank straight away on the number on your card and ask it to stop the payment. Then report it through ReportCyber, which passes cybercrime reports to the Western Australia Police Force. If your identity documents or passwords were shared, IDCARE's free support service can help you lock things down.

    ReportCyber ↗IDCARE ↗

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.

Onslow numbers: questions and answers

Where is the Onslow numbering area?

Onslow is in Western Australia, in the Ashburton council area. The nearest other numbering areas are Exmouth (112 km), Pannawonica (122 km) and Dampier (197 km).

What area code does Onslow use?

Onslow numbers use area code 08. Its register blocks start with 08 91 and 08 51. From overseas, drop the 0 and dial +61 8 followed by the eight-digit local number.

What time zone is Onslow in?

Onslow is on Australian Western Time (AWST, UTC+8), with no daylight saving.

Which carriers hold Onslow phone numbers?

The ACMA register lists 19 carriers with allocated blocks in Onslow. By allocated numbers the largest are Telstra (25%), Symbio Networks (15%) and Soul Pattinson Telecommunications (10%). A number can since have been ported to another provider.

When were Onslow numbers first allocated?

The oldest block on record for Onslow was allocated on 30 June 1991 and is held by Telstra; the newest on 19 August 2026, to Symbio Networks.

How do I report a scam call from a Onslow number?

Report it to Scamwatch. If you lost money, call your bank first, then report it through ReportCyber, which passes it to the Western Australia Police Force. Unwanted sales calls go to the Do Not Call Register's complaint form (1300 792 958).

Check a number from Onslow

Scammers spoof local landline numbers to look nearby. Guides: Australian area codes, how caller ID spoofing works.