Sydenham: landline numbers and carriers

Sydenham is one of the town-level numbering areas the ACMA register uses under area code 03 (VIC & TAS). The register lists 63 number blocks for it with about 259,000 allocated numbers, held by 22 carriers and spread over the 0383…, 0373…, 0393…, 0392…, 0394… and 0399… dialling prefixes. That makes Sydenham the 13th largest of 475 numbering areas under 03 by block count, with 0.75% of the area code's allocated numbers. A landline that calls you from one of these blocks was issued for the Sydenham area — though the line may since have been ported, and caller ID can be spoofed.

Source: ACMA register, data as of 14/10/2026

63blocks in the register
22carriers with allocations
259,000allocated numbers
1991first allocation

Where Sydenham is

State or territory
Victoria
Council area
Brimbank
Local time
— AEST, UTC+10; AEDT, UTC+11 in summer
Number format
03 83xx xxxx; from overseas +61 3 83xx xxxx
Nearest numbering areas
Sunbury (16 km), Craigieburn (19 km), Point Cook (23 km), Melbourne (24 km), Kalkallo (26 km)

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

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

How Sydenham was numbered

The oldest block in Sydenham 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 — 11 of 63 — date from 1990–1994, but allocations here span 35 years. 35 of the blocks are the standard 1,000-number size, and 19 are 10,000 numbers or larger. 14 allocated blocks have changed hands since they were first issued: the register still names AAPT LIMITED, ENGIN PTY LIMITED, GOTALK LIMITED, HUTCHISON TELECOMMUNICATIONS (AUSTRALIA) LIMITED, IPTEL PTY LIMITED, IVOX PTY LTD, POWERTEL LIMITED and RSL COM AUSTRALIA PTY LIMITED as original allocatees of blocks now held by other carriers.

PeriodBlocks allocated
1990–199411
1995–19994
2000–20048
2005–200911
2010–20148
2015–201910
2020–20247
2025–20294

The carriers in Sydenham

TELSTRA LIMITED holds the largest share here with 42.1% of allocated numbers across 21 blocks; OPTUS NETWORKS PTY LIMITED is second with 15.8%, and 20 other carriers hold the rest. TELSTRA LIMITED has the longest tenure, with a block dated 30/06/1991; SYMBIO NETWORKS PTY LTD received the newest, on 19/08/2026. OPTUS NETWORKS PTY LIMITED (2), OPTUS MOBILE PTY LIMITED (1) and PRIMUS TELECOMMUNICATIONS PTY LIMITED (2) hold blocks originally allocated to another carrier.

CarrierBlocksNumbersShareFirst blockLatest block
TELSTRA LIMITED21109,00042.1%30/06/199101/03/2017
OPTUS NETWORKS PTY LIMITED541,00015.8%02/07/199224/08/2006
OPTUS MOBILE PTY LIMITED422,0008.5%30/05/200710/04/2008
PRIMUS TELECOMMUNICATIONS PTY LIMITED413,0005%16/12/200211/02/2014
SOUL PATTINSON TELECOMMUNICATIONS PTY LIMITED413,0005%30/03/200017/06/2021
CHIME COMMUNICATIONS PTY LTD110,0003.9%14/07/200414/07/2004
PIPE INTERNATIONAL (AUSTRALIA) PTY LTD110,0003.9%25/09/200125/09/2001
PIPE NETWORKS PTY LIMITED110,0003.9%14/07/199914/07/1999
TPG TELECOM LIMITED110,0003.9%24/12/199824/12/1998
SYMBIO NETWORKS PTY LTD88,0003.1%24/06/200519/08/2026
NETSIP PTY LTD22,0000.8%14/02/201826/10/2021
ADARGA PTY LTD11,0000.4%16/09/202516/09/2025
AGILE PTY LTD11,0000.4%31/05/200531/05/2005
C2A INTERNET.COM.AU PTY. LTD.11,0000.4%13/07/202313/07/2023
CHECK TECHNOLOGY GROUP PTY LTD11,0000.4%31/01/202231/01/2022
GENNEXT ENTERPRISES PTY LTD11,0000.4%03/10/201903/10/2019
LMGPS LTD11,0000.4%23/11/202323/11/2023
NETERA PTY LTD11,0000.4%24/10/202524/10/2025
PIVOTEL SATELLITE PTY LIMITED11,0000.4%16/04/202516/04/2025
THE TRUSTEE FOR READING FAMILY TRUST11,0000.4%21/10/201921/10/2019
VIRTUTEL PTY LTD11,0000.4%20/12/201520/12/2015
WHY PAY MORE 4 LESS PTY LTD11,0000.4%10/05/201810/05/2018

Number blocks registered for Sydenham

Every registered block for this area is allocated to a carrier. All 63 blocks, ascending:

Block startNumbersOriginal allocateeCurrent holderAllocatedTransferred
0373002000…1,000=VIRTUTEL PTY LTD20/12/2015—
0373005000…1,000=SOUL PATTINSON TELECOMMUNICATIONS PTY LIMITED14/07/2016—
0373008000…1,000=NETSIP PTY LTD14/02/2018—
0373011000…1,000=ADARGA PTY LTD16/09/2025—
0373014000…1,000=THE TRUSTEE FOR READING FAMILY TRUST21/10/2019—
0373025000…1,000=WHY PAY MORE 4 LESS PTY LTD10/05/2018—
0373029000…1,000=SOUL PATTINSON TELECOMMUNICATIONS PTY LIMITED17/09/2019—
0373033000…1,000TWILIO AUSTRALIA PTY LTDSYMBIO NETWORKS PTY LTD24/09/202015/10/2020
0373035000…1,000=GENNEXT ENTERPRISES PTY LTD03/10/2019—
0373036000…1,000=NETSIP PTY LTD26/10/2021—
0373037000…1,000=SYMBIO NETWORKS PTY LTD19/06/2020—
0373040000…1,000=CHECK TECHNOLOGY GROUP PTY LTD31/01/2022—
0373044000…1,000=C2A INTERNET.COM.AU PTY. LTD.13/07/2023—
0373050000…1,000=SOUL PATTINSON TELECOMMUNICATIONS PTY LIMITED17/06/2021—
0373063000…1,000=LMGPS LTD23/11/2023—
0373066000…1,000=PIVOTEL SATELLITE PTY LIMITED16/04/2025—
0373069000…1,000=NETERA PTY LTD24/10/2025—
0373072000…1,000=SYMBIO NETWORKS PTY LTD19/08/2026—
0373776000…4,000=TELSTRA LIMITED01/03/2017—
0373780000…10,000=TELSTRA LIMITED18/03/2015—
0373790000…4,000=TELSTRA LIMITED21/05/2015—
0383040000…10,000HUTCHISON TELECOMMUNICATIONS (AUSTRALIA) LIMITEDTPG TELECOM LIMITED24/12/199828/04/2017
0383080000…10,000AAPT LIMITEDPIPE NETWORKS PTY LIMITED14/07/199924/03/2026
0383150000…10,000IPTEL PTY LIMITEDSOUL PATTINSON TELECOMMUNICATIONS PTY LIMITED30/03/200001/12/2004
0383220000…10,000POWERTEL LIMITEDPIPE INTERNATIONAL (AUSTRALIA) PTY LTD25/09/200124/03/2026
0383370000…10,000=CHIME COMMUNICATIONS PTY LTD14/07/2004—
0383386000…1,000OPTUS NETWORKS PTY LIMITEDOPTUS MOBILE PTY LIMITED30/05/2007—
0383388000…1,000=OPTUS MOBILE PTY LIMITED05/09/2007—
0383482000…1,000GOTALK LIMITEDSYMBIO NETWORKS PTY LTD24/06/200525/07/2013
0383483000…3,000=TELSTRA LIMITED17/12/2008—
0383511000…1,000ENGIN PTY LIMITEDPRIMUS TELECOMMUNICATIONS PTY LIMITED24/12/200411/08/2015
0383517000…1,000=AGILE PTY LTD31/05/200508/02/2011
0383520000…1,000=OPTUS NETWORKS PTY LIMITED20/06/2005—
0383560000…10,000=OPTUS MOBILE PTY LIMITED11/01/2008—
0383570000…10,000=OPTUS MOBILE PTY LIMITED10/04/2008—
0383580000…6,000=TELSTRA LIMITED12/03/2009—
0383610000…10,000=TELSTRA LIMITED17/04/2000—
0383625000…1,000VOXBONESYMBIO NETWORKS PTY LTD10/09/201021/02/2011
0383626000…1,000=TELSTRA LIMITED21/06/2011—
0383628000…1,000=PRIMUS TELECOMMUNICATIONS PTY LIMITED03/02/2012—
0383630000…10,000=OPTUS NETWORKS PTY LIMITED30/06/2004—
0383724000…1,000IVOX PTY LTDSYMBIO NETWORKS PTY LTD18/06/201216/06/2014
0383725000…1,000=TELSTRA LIMITED12/06/2013—
0383726000…4,000=TELSTRA LIMITED27/06/2013—
0383741000…1,000VOCUS PTY LTDPRIMUS TELECOMMUNICATIONS PTY LIMITED11/02/201408/07/2016
0383745000…1,000=SYMBIO NETWORKS PTY LTD24/04/2014—
0383820000…10,000=OPTUS NETWORKS PTY LIMITED24/08/2006—
0383850000…10,000=PRIMUS TELECOMMUNICATIONS PTY LIMITED16/12/2002—
0383900000…10,000=TELSTRA LIMITED06/10/2003—
0392176000…1,000=TELSTRA LIMITED30/06/1991—
0392178000…2,000=TELSTRA LIMITED30/06/1991—
0392193000…1,000=TELSTRA LIMITED30/06/1991—
0392197000…1,000=TELSTRA LIMITED30/06/1991—
0392660000…10,000SINGTEL OPTUS PTY LIMITEDOPTUS NETWORKS PTY LIMITED22/05/199510/02/2003
0393070000…3,000=TELSTRA LIMITED30/06/1991—
0393074000…6,000=TELSTRA LIMITED30/06/1991—
0393240000…10,000SINGTEL OPTUS PTY LIMITEDOPTUS NETWORKS PTY LIMITED02/07/199210/02/2003
0393604000…2,000=TELSTRA LIMITED30/06/1991—
0393610000…10,000=TELSTRA LIMITED30/06/1991—
0393630000…10,000=TELSTRA LIMITED30/06/1991—
0393900000…10,000=TELSTRA LIMITED30/06/1991—
0394490000…10,000=TELSTRA LIMITED15/11/1995—
0399720000…1,000RSL COM AUSTRALIA PTY LIMITEDSYMBIO NETWORKS PTY LTD17/01/200708/10/2009

Numbering areas next to Sydenham in the register

Immediately below and above Sydenham's blocks in the 0383…, 0373…, 0393…, 0392…, 0394… and 0399… prefixes sit Craigieburn, Point Cook, Melbourne, Werribee, Ringwood, Clayton, Croydon and Dandenong.

Numbering areaFirst blockBlocksCarriers
Craigieburn0373000000…6122
Point Cook0373001000…5123
Melbourne0383000000…27313
Werribee0392020000…61
Ringwood0392100000…92
Clayton0392117000…162
Croydon0392120000…82
Dandenong0392121000…71

Had a call from a Sydenham 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 Victoria Police. 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.

Sydenham numbers: questions and answers

Where is the Sydenham numbering area?

Sydenham is in Victoria, in the Brimbank council area. The nearest other numbering areas are Sunbury (16 km), Craigieburn (19 km) and Point Cook (23 km).

What area code does Sydenham use?

Sydenham numbers use area code 03. Its register blocks start with 03 83, 03 73, 03 93, 03 92, 03 94 and 03 99. From overseas, drop the 0 and dial +61 3 followed by the eight-digit local number.

What time zone is Sydenham in?

Sydenham is on Australian Eastern Time (AEST, UTC+10), with daylight saving (AEDT, UTC+11) from the first Sunday in October to the first Sunday in April.

Which carriers hold Sydenham phone numbers?

The ACMA register lists 22 carriers with allocated blocks in Sydenham. By allocated numbers the largest are Telstra (42.1%), Optus Networks (15.8%) and Optus Mobile (8.5%). A number can since have been ported to another provider.

When were Sydenham numbers first allocated?

The oldest block on record for Sydenham 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 Sydenham number?

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

Check a number from Sydenham

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