'Your SIM will be deactivated' texts and calls: O2 and Three scams

The O2 "inactive SIM" text

On 30 June 2026 O2 warned of a phishing scam in which fraudsters pose as O2 and claim customers' SIM cards are about to expire. The text sends you to a fake O2 site that asks you to log in to accept new terms and conditions. O2 says the aim is to get your real login details so the fraudsters can take over your MyO2 account.

O2 says it has blocked over 1 billion scam messages from reaching customers to date, including thousands linked to this scam, and that it blocks known fraudulent web addresses on its network. But scammers keep creating new websites and messages, so some still get through.

The same story by phone, for O2 and Three

• 8 July 2026: Which? warned that the O2 version also arrives as a cold call: you are told your SIM is inactive and will expire, and asked for details to issue a new SIM, over the phone or on a dodgy website.
• 20 August 2026: calls from spoofed UK mobile numbers, claiming to be O2 and offering fake discounts. Which? says the scammer tries to log in to your O2 account, which triggers a one-time passcode text, then tries to get you to read the code out.
• 28 August 2026: calls claiming to be from Three, saying your number will stop working in 24 hours or your SIM card will be blocked. Which? calls this a tactic to get you to reveal personal and payment information.

The pattern is the same each time: a threat to your phone service, a deadline, and a request to log in, give details or read out a code.

What O2 says it does and does not do

• O2 is not contacting customers by text asking them to sign updated terms and conditions or face their SIM being deactivated. Messages like this are a scam.
• On many popular smartphones, genuine O2 messages appear under a verified "O2" contact rather than a standard mobile number.
• Never click a link in an unexpected message. Go straight to the MyO2 app, or call 202 from an O2 phone, to check whether what you are asked to do is real.

On any other network, do the same: check in your network's own app, or call it on the number on its official website, typed in yourself. Never read out a one-time passcode to someone who called you.

How to report the text or the call

• A text: forward it to 7726, free. O2 asks people on every network to do this; the reports help networks block the numbers fraudsters use.
• A call: send a text to 7726 with the word "Call" followed by the number that called you, as the government's Stop! Think Fraud campaign explains.
• A fake website: report it to the NCSC.

If you entered your login or card details

O2 says that if you think you clicked a suspicious link and entered your login details, change your password immediately. Tell your network through its app or official number too: Stop! Think Fraud advises telling any organisation whose name was used. If you also gave card or bank details, call your bank on the number on your card or on 159, and report it to Report Fraud (0300 123 2040; in Scotland, Police Scotland on 101).

Check the number that texted or called you with the UK number checker: if Ofcom has not allocated its range, the caller ID was faked (see what an unallocated number means). Paste the text into the scam text checker; it flags "SIM will be inactive" and "number will stop working" wording. For texts that pretend to be your bank, see the "direct debit set up" scam.

Sources

• Virgin Media O2, inactive SIM warning (30 Jun 2026): Virgin Media O2, 'O2 warns of new inactive SIM scam' (press release, 30 June 2026): "fraudsters pose as the telecoms company and claim customers' SIM cards are about to expire. ... Brits are directed to a fake O2 site – where they're asked to 'login' to accept new terms and conditions. The scam aims to get hold of customers' legitimate login details so fraudsters can take over their MyO2 account. ... O2 has already blocked over 1 billion scam messages from reaching customers to date, including thousands of messages linked to this latest scam. ... scammers constantly evolving their tactics and creating new websites and messages ... O2 is not contacting any customers via text asking them to sign updated Terms and Conditions or face their SIM being deactivated – messages like this are a scam ... genuine messages from O2 will appear under a verified 'O2' contact rather than a standard mobile number. ... go directly to the MyO2 app or call 202 on an O2 device ... Report suspicious messages to 7726 ... If you think you may have clicked on a suspicious link and entered your login details, change your password immediately." — https://news.virginmediao2.co.uk/o2-warns-of-new-inactive-sim-scam-calling-on-customers-to-report-to-7726/, read on 2026-09-30
• Which? scam alerts, O2 and Three (Jul-Aug 2026): Which? scam alerts, 8 July 2026: "The scam message or call claims your SIM is inactive and will expire. You're typically told to give details to issue a new SIM, either over the phone or via a dodgy website."; 20 August 2026: "spoofed UK mobile numbers being used by scammers claiming to be from phone company O2 offering fake discounts on your phone bill. The scammer will already have enough details about you to attempt to log in to your O2 account, and these login attempts will trigger a one-time passcode text. The scammer's goal is to then get you to reveal the passcode so they can gain full access to your account."; 28 August 2026: "Scammers claiming to be from mobile network Three are making calls telling you that your number will stop working in 24 hours or that your Sim card will be blocked. This is a tactic used by scammers to try to get you to reveal personal and payment information." — https://www.which.co.uk/news/article/the-latest-scam-alerts-from-which-aBRLy2b02WkC, read on 2026-09-30
• Stop! Think Fraud, reporting: Stop! Think Fraud (UK Government campaign), Reporting fraud: "Report suspicious phone calls and text messages free of charge to 7726. To report a phone call, simply send a text to 7726 with the word 'Call' followed by the scam caller's number. ... If you've lost money or you think a fraudster has access to your bank account, tell your bank ... Always contact them directly using a known email or phone number, such as the ones shown on their website or the back of your card, or call 159. ... contact any other relevant organisation ... an organisation whose name was falsely used in the fraud (such as an energy provider or Driver and Vehicle Licensing Agency) ... Before you delete the email, forward it to report@phishing.gov.uk ... Report suspicious websites to the National Cyber Security Centre" — https://stopthinkfraud.campaign.gov.uk/reporting-fraud/, read on 2026-09-30
• NCSC, forwarding to 7726: NCSC, Report a scam text: "Most phone providers are part of a scheme that allows customers to report suspicious text messages for free by forwarding it to 7726. If you forward a text to 7726, your provider can investigate the origin of the text and arrange to block or ban the sender, if it's found to be malicious." — https://www.ncsc.gov.uk/collection/phishing-scams/report-scam-text-message, read on 2026-09-29
• Report Fraud: Action Fraud / City of London Police press release, 4 Dec 2025: "From Thursday 4 December 2025, anyone needing to report cyber crime or fraud will be directed to our new Report Fraud service. Report Fraud has replaced Action Fraud, for use in England, Wales and Northern Ireland. People affected by cyber crime or fraud in Scotland should continue to call Police Scotland using the 101 telephone number. ... reportfraud.police.uk or by calling 0300 123 2040." — https://www.wired-gov.net/wg/news.nsf/articles/Report+Fraud+service+goes+live+04122025143000; https://www.reportfraud.police.uk/, read on 2026-09-29