United Kingdom phone code +44: mobile format & how to dial

Key facts

International code+44

International format+44 XXXX XXXXXXe.g. +44 7700 900123

Mobile prefixes7XXX XXXXXXe.g. 7700 900123

Mobile length10 digits

Landline format0XXXX XXXXXXe.g. 020 7946 0123

Domestic trunk0

How to read a number

+447700900123

+44Country code: United Kingdom.
7Mobile indicator: Written 07 domestically — the 0 is the trunk prefix. Real mobiles are 071–075 and 077–079; 070 is personal (forwarding) numbering and 076 is paging, neither is a mobile.
700900123Remaining 9 digits: The leading digits are the block Ofcom allocated to a carrier; with portability you can’t tell the current carrier.

Domestic format: 07700 900123. 07700 900000–900999 in the example is reserved by Ofcom for fiction. Landlines starting 01 and 02 are geographic, e.g. London is 020.

This section checked 2026-09-13. Sources: www.ofcom.org.uk/phones-and-broadband/phone-numbers/numbers-for-drama · www.ofcom.org.uk/phones-telecoms-and-internet/information-for-industry/numbering/070-guidance · onsim.uk/uk-dialling-codes/

Number ranges & quality

Range	Type	Notes
`Starts with 07 (071xx / 074xx / 075xx / 077xx / 078xx / 079xx)`	Mobile carrier	UK mobile ranges.
`0700`	Other	Personal numbers (forwarding), not mobile — sign-ups get rejected.
`0300 / 0800 / 0845`	Other	Non-geographic numbers, not mobile.

Intl SMSStable

Virtual-number riskLow

ID requiredPrepaid ID requirements are relaxed.

Physical SIMs starting with 07 are fine for everything. 0700 is a forwarding number and will be rejected by platforms when used to sign up.

Carriers & prefixes

Mobile prefixes by carrier.

Number portability applies — a prefix only shows the original carrier.

EE Mobile carrier

Owned by BT.
Virgin Media O2 Mobile carrier

Notable brands: O2, giffgaff

Tesco Mobile and Sky Mobile also run on its network.
VodafoneThree Mobile carrier

Notable brands: Vodafone, Three, VOXI, SMARTY

Merged in May 2025; iD Mobile and Lebara also run on its network.

This section checked 2026-09-13. Sources: www.ispreview.co.uk/index.php/2025/06/vodafone-and-three-uk-officially-complete-16bn-mega-mobile-merger.html · mobileecosystemforum.com/2025/07/29/drama-and-dynamics-the-state-of-the-uks-mvno-market/

SIM cards & keeping a number

The UK is one of the most popular “keep a number” countries among Chinese-speaking users, mainly thanks to giffgaff: the SIM is free, a £10 top-up activates it, and one chargeable action every 6 months keeps the number alive. Receiving SMS while roaming in China is free. It runs on O2, so it is a genuine carrier number that overseas platforms readily accept.

Note: from 2026 giffgaff no longer ships physical SIMs to mainland China — most people now use eSIM or have a card forwarded. If you forget the 6-month rule, the number is reclaimed and can’t be restored.

giffgaff

Number-keeping SIM

Network: MVNO on O2 (Virgin Media O2)
Price: Free SIM; a £10 top-up is required to activate. eSIM available since October 2023
Keeping the number: At least one call, SMS, data session or top-up every 6 months. Warning emails go out a month and 5 days before; once deactivated the balance is lost and the SIM can’t be reactivated, though a PAC code can be requested within 30 days to port the number out. The cheapest way from China is one SMS every six months.
ID check: No ID required
SMS & calls: Incoming SMS free while roaming in China; outgoing SMS about £0.30 each

Reported sign-up results

TelegramWorksChatGPTWorksWhatsAppWorks

Pros

Free SIM, no monthly fee — one SMS every six months keeps it
A genuine carrier number on O2, widely accepted by platforms
Incoming SMS free while roaming in China

Watch out

No direct shipping to mainland China since 2026
Miss the 6-month rule and the number and balance are gone
Platform results come mainly from SIM sellers and Chinese guides; individual platforms may differ

Where to buy: giffgaff.com

Sources: help.giffgaff.com/en/articles/242797-understanding-why-your-number-has-been-deactivated · community.giffgaff.com/t5/Help-Support/SIM-deactivation-after-6-months-without-a-chargeable-event/td-p/96035 · buyhksim.com/guide-giffgaff.php · www.giffgaff.im/guides/usage

From user and blogger reports; platform risk rules change often — treat as a guide only. This section checked 2026-09-14.

Sign-up availability

What to expect when signing up for these services with a physical SIM from this country:

ChatGPT Works

Claude Works

WhatsApp Works

Telegram Works

LINE Works

WeChat Works

X Works

TikTok Works

Gemini Works

Jump to another country

Calling United Kingdom from abroad

Dial +44, then the local number. Drop the leading trunk prefix 0. E.g. the landline 020 7946 0123 is dialled from abroad as +44 20 7946 0123.

Generate the full number →

Dialing within United Kingdom

For domestic long distance dial 0 first, then the area code. Local calls and mobiles: dial directly.

Elsewhere in Europe

Community tips

英国预付费 SIM（Giffgaff、EE 等）基本不查身份，便利店就能买，收验证码很稳。

个人实测 · 2026-09
Giffgaff 免费收短信，注册各类海外账号都好用，门槛也低。

reddit · 2026-09

Reader-reported, for reference only; not a registration guarantee. Official platform rules apply. Tips are shown in the original language as submitted.

Have experience to share? Submit →

Common premise & disclaimer

Applies to every platform: VoIP / virtual numbers and heavily-reused number pools get rejected. Physical SIM only.

Checked 2026-09-12. Platform region policies and number-range allocations change — always confirm against each platform’s official supported-regions list and the carrier’s notices.

Sources：help.openai.com/articles/7947663 · support.google.com/gemini?p=gemini_web_availability

United Kingdom +44