How to screen calls on your iPhone, Android phone and landline to avoid scammers

Scam calls to your smartphone or landline can be disruptive at best and financially devastating at worst, often aiming to convince you to hand over personal information.

Luckily, there are various ways to combat them. On many Android phones, for example, you can use Google Assistant to answer calls from unknown numbers – it identifies who is calling and why before you even answer. Meanwhile, iPhone users can silence unknown callers and filter suspected scam calls automatically.

Below, we explain in simple terms how to keep scam calls at bay on your mobile, plus explain how rigorous Which? tests have uncovered brilliant call-blocking landline phones.

Jump to: Screen calls on iPhone | Screen calls on Android | Block calls on a landline

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 How to screen calls on an iPhone

iPhone owners can try Apple's Call Screening feature to act as a barrier between you and potential scam calls. This feature comes with iOS26 (check which version of iOS you're on via Settings > General > Update) - if you haven't installed it, you can do so in General by selecting Software Update.

To screen or silence unknown numbers on your iPhone, try this:

1. Go to your Settings menu
2. Select Apps > Phone
3. Choose between Ask Reason for Calling (calls from unknown numbers are asked for more information before your iPhone rings) or Silence (calls from unsaved numbers are silenced, sent to voicemail and still appear in your Recents list).

Note that you can also block calls from specific people or numbers. To do so, go to the Phone app, then select Contacts. Tap a contact, then choose Block Contact. If you need to undo those changes, go to Settings > Apps > Phone > Blocked Contacts > Edit.

See also: 10 things every smartphone owner should do to keep their data safe.

How to screen calls on Android

On Android, many phones offer automatic call screening and spam detection features to help protect you from scam calls.

To screen calls on Android, try this:

1. Go to the Phone app and select Settings
2. Select Call Screen or Caller ID & spam, depending on your phone
3. Turn on call screening or spam protection for unknown callers

On Google Pixel phones, when you receive a call from an unknown number, you’ll see an option to Screen call. Tapping it lets Google Assistant answer on your behalf and displays a transcript of the caller’s response, so you can decide whether to answer or hang up.

If you don’t have a Google Pixel, you won’t see Call Screen. However, most Android phones still include basic spam detection that flags or silences suspected scam calls before you pick up.

You can also block calls from specific numbers. To do this, open the Phone app, tap the caller’s contact card and select Block. To unblock numbers, go to Settings > Blocked numbers.

How to block calls on a landline

According to a study from the financial industry association UK Finance, we collectively lost more than £629m to scams in the first half of 2025, and this is likely underreported.

While much of what scammers get up to has moved online, call-based scams remain a sizable proportion of reported cases, at one in six. But you can fight back.

Try a call-blocking phone

Thanks to our tests, we know the handset you use can make a difference. The best cordless phones have strong and easy-to-use call-blocking features, which could prove invaluable in protecting you and your loved ones against persistent scammers.

We’ve seen excellent call-blocking features, including blocklists that can stop entire categories of numbers, features that prevent all but designated contacts from connecting, and dedicated block buttons that reject and add numbers to the phone’s blocklist.

Choosing a phone with effective call-blocking is not only a good idea for yourself if you have a landline, but also for any vulnerable friend or family member who you want to protect from scam calls.

Best cordless phones – we've tested cordless landline phones from BT, Gigaset, Panasonic and more to find out which offer the effective call blocking, crystal clear calls, good range and are easy to use.

Be aware of common scams (and how to report them)

The most common call-based scam, known as spoofing, involves criminals imitating legitimate organisations such as banks, HMRC, Amazon, local councils seeking ‘unpaid’ tax, ‘undercover’ police, pension providers and debt-management firms. The aim is to get people to hand over money and/or private information.

Criminals can commit fraud cheaply and successfully using technology such as AI voice deepfakes that mimic real people. They can also target UK landlines with the help of technology such as caller ID generation, spoofing kits (which allow foreign criminals to appear to be calling from a UK number) and vishing kits (where callers trick you into calling a premium number).

Ofcom now forces UK phone providers to block calls from abroad that spoof UK landlines. BT voluntarily implemented this policy earlier than January 2025 deadline, and within the very first month, it prevented a whopping one million calls per day. Ofcom also plans to make telecoms companies withhold unverified caller IDs from UK mobiles roaming abroad.

Our expert says

'You can report scam calls to landlines on the Report fraud website (formerly Action Fraud). If you live in Scotland, report it directly to the police by calling 101.

'It’s vital that we all report dodgy numbers, as this can help lead to the closure of scamming operations, along with the prosecution of individuals involved. Help to make scammers fear the consequences of calling you.'

Callum Pears, Which? cordless phones expert

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