UK area code

01603 area code — Norwich

01603 is Ofcom’s Norwich numbering area, in Norfolk, East of England England. 90 phone companies hold its 367 allocated number blocks. Its numbers are written like 01603 234 567. The nearest other codes are 01508 Brooke (11 km) and 01953 Wymondham (14 km).

01603 at a glance

Ofcom area name: Norwich
County: Norfolk
Council area: Norfolk
Region: East of England England
Number format: 01603 234 567 (4+6)
Local calls: Full number recommended
Current code since: 1995 (previously 0603)
Allocated blocks: 367 of 469 (78%) across 90 providers
Newest block: 3 June 2026 (5 in the last 12 months)
Nearest codes: 01508 Brooke (11 km), 01953 Wymondham (14 km), 01986 Bungay (22 km), 01692 North Walsham (22 km)

Sources: Ofcom numbering data (weekly) and area-code list, Ofcom Numbering Plan, ONS geography.

Map of the 01603 Norwich dialling area and the nearest other UK area codes — Shaded: the council area containing the code's main exchange town (Norfolk). Ofcom doesn’t publish exchange boundaries, so this shows where the numbering area’s town is, not an exact outline. Boundaries: ONS (OGL); places: ONS Index of Place Names.

If a 01603 number called you

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

1
Call back on a number you trust
If a caller says they're your bank, HMRC, a courier or a council, 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
Forward it to 7726
On a mobile, copy the caller's number from your recent calls and text it to 7726 (it spells SPAM). Scam texts can be forwarded to 7726 as they are. It's free, and your network uses the reports to investigate and block numbers.
Ofcom: what to do about a scam call ↗
3
Stop sales calls
Register your landline and mobile free with the Telephone Preference Service (0345 070 0707). Legitimate UK marketers must check it; calls should drop within 28 days. It won't stop scammers.
Telephone Preference Service ↗
4
If you lost money or shared details
Call your bank on the number on your card (or 159 to reach most UK banks safely), then report it to Report Fraud online or on 0300 123 2040. Report Fraud replaced Action Fraud on 4 December 2025 for England, Wales and Northern Ireland; in Scotland call Police Scotland on 101.
159 (Stop Scams UK) ↗Report Fraud ↗

01603 history and number format

Number format: Numbers on 01603 use Ofcom's 4+6 format: the 5-digit code (including the leading 0) followed by a 6-digit local number — written like 01603 234 567.

Before 1995: 01603 took its current form at PhONEday on 16 April 1995, when a "1" was inserted into every UK geographic code — before that the area dialled 0603.

Local dialling: Traditionally not from another 01603 landline, but it now depends on your provider: Ofcom stopped requiring providers to offer local (code-free) dialling on 11 March 2022. Dialling 01603 first always works, and mobiles always need it.

Allocation record: the oldest number block still visible on 01603 was allocated on 15 July 1994, and the most recent on 3 June 2026. 5 blocks were allocated in the last 12 months — newly-activated ranges with no call history, which is worth knowing when an unfamiliar 01603 number rings (see the weekly numbering changelog for every new allocation.)

Phone companies holding 01603 numbers

Every Ofcom range holder with blocks on 01603, by allocated blocks. The holder is the company Ofcom allocated the block to; a number can since have been ported to another provider (see range holder vs current provider).

Range holder	Allocated	All blocks	First block	Latest block
BT	123	123	15 July 1994	19 February 2024
Vodafone Ltd (C&W)	36	36	18 June 2013	10 November 2021
Gamma Telecom Holdings Limited	30	30	1 March 2004	3 June 2026
Sky UK Limited	23	23	2 July 2013	14 December 2022
Virgin Media Limited	15	15	27 January 1997	14 October 2015
TalkTalk Communications Limited	14	14	31 August 2011	21 November 2018
Colt Technology Services	10	10	20 October 2011	15 May 2025
GCI Network Solutions Limited	7	7	25 April 2017	22 December 2023
Magrathea Telecommunications Limited	7	7	16 November 2011	16 November 2011
TGL Services (UK) Ltd	4	4	2 February 2015	2 February 2015
Voxbone SA	4	4	29 January 2008	20 November 2025
Lumen Technologies UK Limited	3	3	3 April 2006	3 March 2009
Media Hawk Ltd	3	3	10 April 2013	25 November 2015
Redcentric Solutions Limited	3	3	5 June 2015	5 June 2015
Calltracks Limited	2	2	23 September 2013	12 January 2022
DRD Communications Limited	2	2	5 October 2023	5 October 2023
Datazero Ltd	2	2	2 November 2010	12 April 2019
Digital Space Group Limited	2	2	15 March 2016	12 April 2016
IOVOX Limited	2	2	3 July 2012	23 October 2014
Twilio Ireland Limited	2	2	13 October 2020	19 August 2024
Verizon UK Limited	2	2	21 November 2014	21 November 2014
VoiceHost Limited	2	2	30 June 2010	30 June 2010
Voiceflex Limited	2	2	30 July 2007	18 April 2023
(AQ) LIMITED	1	1	11 September 2012	11 September 2012
24 Seven Cloud Communications Ltd	1	1	21 January 2020	21 January 2020
8x8 Communications UK Limited	1	1	5 April 2012	5 April 2012
8x8 UK Limited	1	1	19 February 2010	19 February 2010
AQL Wholesale Ltd	1	1	1 November 2004	1 November 2004
Alnitak GmbH	1	1	31 August 2016	31 August 2016
Andrews & Arnold (Numbers) Ltd	1	1	23 March 2009	23 March 2009

Showing the 30 largest of 90 holders.

Openreach exchanges at Norwich

Exchanges Openreach lists at this location in its copper stop-sell programme, with the date new copper orders stop.

Thorpe (TCU) EATHPStop sell 06-Nov-25 · Tranche 18

All number blocks on 01603first 200 of 469, by prefix

Prefix	Status	Range holder
+44 160300	Protected	—
+44 160301	Protected	—
+44 160302	Protected	—
+44 160303	Protected	—
+44 160304	Protected	—
+44 160305	Protected	—
+44 160306	Protected	—
+44 160307	Protected	—
+44 160308	Protected	—
+44 160309	Protected	—
+44 1603100	Protected	—
+44 1603101	Protected	—
+44 1603102	Protected	—
+44 1603103	Protected	—
+44 1603104	Protected	—
+44 1603105	Protected	—
+44 1603106	Protected	—
+44 1603107	Protected	—
+44 1603108	Protected	—
+44 1603109	Protected	—
+44 160311	Protected	—
+44 160312	Protected	—
+44 160313	Protected	—
+44 160314	Protected	—
+44 160315	Protected	—
+44 160316	Protected	—
+44 160317	Protected	—
+44 160318	Protected	—
+44 160319	Protected	—
+44 160320	Allocated	Vodafone Ltd (C&W)
+44 1603210	Allocated	BT
+44 1603211	Allocated	BT
+44 1603212	Allocated	TELNYX UK LIMITED
+44 1603213	Allocated	BT
+44 1603214	Allocated	BT
+44 1603215	Allocated	BT
+44 1603216	Allocated	BT
+44 1603217	Allocated	BT
+44 1603218	Allocated	BT
+44 1603219	Allocated	BT
+44 160322	Allocated	BT
+44 160323	Allocated	BT
+44 1603240	Allocated	BT
+44 1603241	Allocated	BT
+44 1603242	Allocated	BT
+44 1603243	Allocated	BT
+44 1603244	Allocated	Colt Technology Services
+44 1603245	Allocated	BT
+44 1603246	Allocated	BT
+44 1603247	Allocated	BT
+44 1603248	Allocated	BT
+44 1603249	Allocated	Twilio Ireland Limited
+44 160325	Allocated	BT
+44 1603260	Allocated	BT
+44 1603261	Allocated	BT
+44 1603262	Allocated	BT
+44 1603263	Allocated	BT
+44 1603264	Allocated	BT
+44 1603265	Allocated	Voxbone SA
+44 1603266	Allocated	BT
+44 1603267	Allocated	Gamma Telecom Holdings Limited
+44 1603268	Allocated	BT
+44 1603269	Allocated	BT
+44 160327	Allocated	BT
+44 160328	Allocated	BT
+44 1603290	Allocated	Net-Work Internet Ltd
+44 1603291	Allocated	TalkTalk Communications Limited
+44 1603292	Allocated	Invade International Ltd
+44 1603293	Allocated	VoIP-Un Limited
+44 1603294	Allocated	GCI Network Solutions Limited
+44 1603295	Allocated	Digital Space Group Limited
+44 1603296	Allocated	Telecom2 Limited
+44 1603297	Free	—
+44 1603298	Allocated	Voxbone SA
+44 1603299	Allocated	Nationwide Telephone Assistance Ltd
+44 160330	Allocated	BT
+44 1603310	Allocated	Nodemax Limited
+44 1603311	Free	—
+44 1603312	Free	—
+44 1603313	Free	—
+44 1603314	Allocated	GCI Network Solutions Limited
+44 1603315	Allocated	Barritel Limited
+44 1603316	Allocated	Served Up Limited
+44 1603317	Protected	—
+44 1603318	Allocated	Barritec Limited
+44 1603319	Allocated	Vonage Business Limited
+44 1603320	Allocated	BT
+44 1603321	Allocated	Andrews & Arnold (Numbers) Ltd
+44 1603322	Allocated	Sky UK Limited
+44 1603323	Allocated	TalkTalk Communications Limited
+44 1603324	Allocated	INTELLIGENT EXCHANGES LIMITED
+44 1603325	Allocated	Gamma Telecom Holdings Limited
+44 1603326	Allocated	Lumen Technologies UK Limited
+44 1603327	Allocated	Inet Telecoms Ltd (Voipfone)
+44 1603328	Allocated	Sky UK Limited
+44 1603329	Allocated	Telecoms World Limited
+44 1603330	Protected	—
+44 1603331	Allocated	BT
+44 1603332	Quarantined	—
+44 1603333	Allocated	Gamma Telecom Holdings Limited
+44 1603334	Allocated	Invoco Ltd
+44 1603335	Allocated	Sky UK Limited
+44 1603336	Allocated	YayYay Limited
+44 1603337	Allocated	Gamma Telecom Holdings Limited
+44 1603338	Allocated	Nuso Cloud UK Limited
+44 1603339	Allocated	Buzz Networks Limited
+44 160334	Allocated	AQL Wholesale Ltd
+44 160335	Allocated	Vodafone Ltd (C&W)
+44 1603360	Allocated	GCI Network Solutions Limited
+44 1603361	Allocated	Twilio Ireland Limited
+44 1603362	Allocated	Sky UK Limited
+44 1603363	Allocated	Colt Technology Services
+44 1603364	Allocated	Gamma Telecom Holdings Limited
+44 1603365	Allocated	Gamma Telecom Holdings Limited
+44 1603366	Protected	—
+44 1603367	Allocated	Gamma Telecom Holdings Limited
+44 1603368	Protected	—
+44 1603369	Allocated	Gamma Telecom Holdings Limited
+44 1603370	Allocated	Verizon UK Limited
+44 1603371	Allocated	Verizon UK Limited
+44 1603372	Protected	—
+44 1603373	Protected	—
+44 1603374	Protected	—
+44 1603375	Protected	—
+44 1603376	Protected	—
+44 1603377	Protected	—
+44 1603378	Protected	—
+44 1603379	Protected	—
+44 1603380	Allocated	8x8 UK Limited
+44 1603381	Allocated	Liquid 11 Limited
+44 1603382	Protected	—
+44 1603383	Allocated	Minotaur Telecom Limited
+44 1603384	Allocated	Calltracks Limited
+44 1603385	Allocated	Voxbone SA
+44 1603386	Protected	—
+44 1603387	Allocated	Sky UK Limited
+44 1603388	Allocated	Suretec Systems Ltd
+44 1603389	Allocated	Datazero Ltd
+44 1603390	Protected	—
+44 1603391	Allocated	8x8 Communications UK Limited
+44 1603392	Allocated	ICC Networks Ltd
+44 1603393	Allocated	TalkTalk Communications Limited
+44 1603394	Allocated	Ziron Limited
+44 1603395	Allocated	Sky UK Limited
+44 1603396	Allocated	TalkTalk Communications Limited
+44 1603397	Allocated	Gamma Telecom Holdings Limited
+44 1603398	Allocated	IOVOX Limited
+44 1603399	Allocated	Datazero Ltd
+44 160340	Allocated	BT
+44 160341	Allocated	BT
+44 160342	Allocated	BT
+44 160343	Allocated	BT
+44 160344	Allocated	Virgin Media Limited
+44 160345	Allocated	BT
+44 160346	Allocated	Virgin Media Limited
+44 160347	Allocated	Virgin Media Limited
+44 160348	Allocated	BT
+44 160349	Allocated	Virgin Media Limited
+44 160350	Allocated	BT
+44 160351	Allocated	Gamma Telecom Holdings Limited
+44 1603520	Allocated	Windsor Telecom Limited
+44 1603521	Protected	—
+44 1603522	Allocated	Ccpro Solutions Limited
+44 1603523	Allocated	Core Telecom Limited
+44 1603524	Protected	—
+44 1603525	Allocated	Citrus Telecommunications Ltd
+44 1603526	Allocated	Sky UK Limited
+44 1603527	Allocated	Sky UK Limited
+44 1603528	Allocated	Sky UK Limited
+44 1603529	Allocated	HAVENSTOKE COMMUNICATIONS LTD
+44 1603530	Allocated	TGL Services (UK) Ltd
+44 1603531	Allocated	BT
+44 1603532	Allocated	TGL Services (UK) Ltd
+44 1603533	Allocated	TGL Services (UK) Ltd
+44 1603534	Allocated	TGL Services (UK) Ltd
+44 1603535	Allocated	GCI Network Solutions Limited
+44 1603536	Allocated	BT
+44 1603537	Allocated	Gamma Telecom Holdings Limited
+44 1603538	Protected	—
+44 1603539	Allocated	SiPalto Ltd
+44 1603540	Allocated	Vodafone Ltd (C&W)
+44 1603541	Allocated	Telappliant Limited
+44 1603542	Allocated	Gamma Telecom Holdings Limited
+44 1603543	Allocated	Vodafone Ltd (C&W)
+44 1603544	Allocated	Vodafone Ltd (C&W)
+44 1603545	Allocated	Vodafone Ltd (C&W)
+44 1603546	Allocated	Vodafone Ltd (C&W)
+44 1603547	Allocated	Vodafone Ltd (C&W)
+44 1603548	Allocated	Vodafone Ltd (C&W)
+44 1603549	Allocated	Vodafone Ltd (C&W)
+44 1603550	Allocated	Lumen Technologies UK Limited
+44 1603551	Allocated	BT
+44 1603552	Allocated	Kalnet4U Ltd
+44 1603553	Allocated	Lumen Technologies UK Limited
+44 1603554	Allocated	Digital Mail Limited
+44 1603555	Allocated	Simwood eSMS Limited
+44 1603556	Protected	—
+44 1603557	Allocated	TelNG Limited
+44 1603558	Allocated	Voiceflex Limited
+44 1603559	Allocated	VoiceHost Limited

FAQs about 01603

Where is area code 01603?

01603 is Ofcom's Norwich numbering area, in Norfolk, East of England England. Its exchange town is in Norfolk. From abroad, drop the 0 and dial +44 1603.

Do I need to dial 01603 for a local call?

Traditionally not from another 01603 landline, but it now depends on your provider: Ofcom stopped requiring providers to offer local (code-free) dialling on 11 March 2022. Dialling 01603 first always works, and mobiles always need it.

How are 01603 numbers written?

Numbers on 01603 use Ofcom's 4+6 format: the 5-digit code (including the leading 0) followed by a 6-digit local number — written like 01603 234 567. From abroad the leading zero is dropped: +44 1603 then the local number.

What was the 01603 area code before?

01603 took its current form at PhONEday on 16 April 1995, when a "1" was inserted into every UK geographic code — before that the area dialled 0603. Old signage or stationery showing 0603 refers to the same Norwich numbers.

Which phone companies hold 01603 numbers?

Ofcom lists 90 providers with allocated blocks on 01603. The largest are BT with 123 of the 367 allocated blocks, Vodafone with 36 of the 367 allocated blocks and Gamma Telecom Holdings Limited with 30 of the 367 allocated blocks. Numbers can be ported, so a number's current provider may differ from the block's holder.

Which area codes are next to 01603?

By distance between exchange towns, the nearest other codes are 01508 Brooke (11 km), 01953 Wymondham (14 km), 01986 Bungay (22 km) and 01692 North Walsham (22 km).

How do I report a scam call from a 01603 number?

On a mobile, text the caller's number to 7726 (free). If you lost money or shared details, call your bank and report it to Report Fraud (0300 123 2040), which replaced Action Fraud in December 2025. Unwanted sales calls go to the ICO after registering with the Telephone Preference Service.