Nuisance calls are the bane of the modern age. Fortunately you can block specific callers (or rather, specific phone numbers) on your iPhone, enabling you to avoid them safely without having to cut yourself off from the people you do want to talk to.

In the old days, blocking an incoming number on an iPhone required complicated workarounds or jailbreaking. But that all changed back in 2013 with the introduction of iOS 7 and its user-friendly number-blocking feature. In this tutorial we show how to block an unwanted caller's phone number on any iPhone, running any version of iOS, even if they've hidden their caller ID in an effort to get round the standard call-blocking procedure.

For related advice, take a look at our guide showing how to block and report iMessage spam. And here is how to tell if someone has blocked you.

How to block numbers on an iPhone

Let's start with the easier task. Blocking a phone number on an iPhone running iOS 7 or later is simple.

Let's imagine that you receive a call, hang up (or don't answer), and then decide you want to block that person's number and avoid being bothered by them in the future.

Simply go to your list of recent callers (open the Phone app, then hit the Recents tab at the bottom). Click the 'i' symbol next to the unwanted number, scroll down and tap Block this Caller, then confirm your decision. You won't be bothered with any calls, texts or FaceTime calls from that number.

(When we tried calling an iPhone that had blocked us, we heard a single ring, and were then diverted to the O2 messaging service, where we recorded a message. But the iPhone didn't ring, or show the number in its recent calls. We were able to find the voicemail in the end, but it wasn't stored in the normal place, but in a special blocked folder - and we weren't notified about the message being left.)

How to block a number on iPhone

Alternatively, go to the Settings app, scroll down and tap Phone. Tap Call Blocking & Identification, and you'll see your list of blocked callers. Hit Block Contact and pick further numbers to block from your contacts list. (You'd need to add the nuisance caller to your contacts list for this method to work, however.)

How to unblock numbers

If you change your mind and decide to unblock the number, go to Settings > Phone > Call Blocking & Identification and hit Edit. Tap the red circle next to the blocked number you want to unblock, and a red Unblock button will appear. Tap that.

How to block a number on iPhone: Unblocking

Alternatively - and more helpfully if you change your mind immediately after setting up the block - you can simply tap the 'Block this caller' option again, after clicking the 'i' symbol next to a recent number (it changes to 'Unblock this caller' when you block them).

Use a call-blocking app

While you can block specific numbers using the above method, iOS 10 introduced the ability to block all spam calls from your iPhone - from numbers associated with telemarking companies and the like, anyway. Apple opened up iOS 10 to developers, allowing them to be able to do more than before - including screening your incoming phone calls, thanks to CallKit.

One app that looks to provide this for users is Callblock. Simply download the app, select the kinds of calls you'd like to block and voila! It should block all nuisance callers whose details are on the apps 200,000-entry database. Even if it isn't, it's easy enough to add new numbers yourself via the app.

How to block a number in iOS 6 or earlier

The advice we'd offer first of all is to update to the latest version of iOS - this is a free process and brings a phenomenal number of useful features that have been added to iOS since 2013. However, some devices simply can't update beyond a certain point, so this may not be possible.

You can still block a number on an iPhone running iOS 6, but it's a lot trickier. There are two main techniques.

1. Jailbreak your iPhone, and block numbers using iBlacklist or another unofficial app

'Jailbreaking' your iPhone means bypassing the locks put in place by Apple to prevent unauthorised apps being used on the phone. Once you break these restrictions, you gain access to a large number of unofficial apps, many of which offer features you'd never otherwise be able to access; but jailbreaking is legally ambiguous, risky, and certain to void any warranties you have with Apple. Therefore our advice is to think long and hard before going ahead.

(What's more, the known methods for jailbreaking the iPhone 4S and later won't work if you've updated to iOS 6.1.3 or later, so you'll have to jump ahead to solution 2.)

Assuming you've heard and understood our warnings and still want to go ahead, a separate article provides full iPhone jailbreaking instructions. As we said, you'll need to be using iOS 6.1.2 or earlier to achieve a long-term jailbreak - later updates fixed the flaw that allowed the process to work.

How to block a number in iOS 6 or earlier: iBlacklist Cydia app

Once you've jailbroken your iPhone, you need to find a call-blocking app. Search on the Cydia app store. The blocking app we used is called iBlacklist, which offers the ability to block calls and SMS messages from specific numbers, as well as all unknown numbers.

Install iBlacklist, restart your iPhone, open iBlacklist and click 'Blacklists'. To add a phone number to your blacklist, hit 'Add new Blacklist' and add it manually (you can do this via your recent call list). Once you've added a number, set the 'Call' icon to 'On'. To block text messages do the same thing with the 'Message' icon.

Now you need to configure what happens when a call comes in from a blacklisted number. Hit 'Action to be performed'. Options include blocking before your phone even acknowledges the call, returning an engaged tone, sending directly to voicemail, or automatically hanging up. Finally, hit the blue button to save your selections.

2. Set up an 'unwanted caller' contact

If you don't like the idea of jailbreaking your iPhone, try this canny workaround.

Create a contact from the number you were called on. Instead of naming it after the person or company, however, call the contact 'Nuisance Caller', 'Hang Up' or some other label that you'll understand.

How to block a number on iOS 6 or earlier: Create a Nuisance Caller contact

When it comes up you'll know that it's an unwanted caller, and won't pick up.

How to block numbers on iOS 6 or earlier: Unwanted caller iPhone Contact

And it doesn't just work on one number. Every time a different timewaster calls you, simply bring up the recent calls screen, tap the arrow by the number and hit 'Add to Existing Contact'. Then add them to the previously created contact.

But wait: it gets better. To save you the trouble of looking at your phone to see who's calling, you can set a specific ringtone to the troublemaker contact. The robot, say, or the quacking duck - or better still, a silent ringtone. You'll need to create the ringtone yourself, but it's very easy. Just create a silent sample in GarageBand, then save it as a ringtone.

How to block a number when caller ID is hidden

It's fairly well known that basic call blocks are easy to bypass. All you need to do is hide your caller ID; you can do this in your iPhone's settings, or enter a country-specific code on a call-by-call basis. With no caller ID, the iPhone doesn't know who's calling, and therefore can't block the call, although it will indicate that the number has been withheld, that there is no caller ID, or that the caller is unknown.

(It strikes us as odd that Apple doesn't give you the option to block all unknown calls. Android offers this feature. It would be a good one to think about for iOS 14.)

Fortunately, for those who are being harassed by persistent, abusive or stalking callers who know about this simple workaround, there are some options remaining. Here's what you need to know in order to block an unknown number.

Is the number hidden, or simply unknown?

Firstly, it may be worth clarifying the difference between hidden and unknown numbers.

Unknown are those contacts that your telephone company cannot recognise. (Calls from telemarketers tend to come under this category.) Whereas a hidden number, also called a private number, is the contact of someone who is consciously withholding his or her caller ID.

But in both cases, you cannot call back or see the number on your phone. The blocking method that we have described before is not going to work with private and unknown calls. So what to do in those cases?

Download a call-blocking app

There are some apps available from the App Store that can block calls from hidden numbers. Call Bliss (£9.99/$9.99), for example, silences unwanted calls or sends them to your voice mail.

However, we cannot vouch for the reliability of these apps; plus, they are usually paid apps. Some others might be free but have in-app purchases, meaning you'll need to pay in order to upgrade them.

Use Do Not Disturb

Another option is to customise Do Not Disturb in order to silence calls from the contacts your phone doesn't recognise.

Go to Settings > Do Not Disturb > Allow Calls From. Select the option All Contacts, which means you will receive calls only from those in your contact list.

Subscribe to TrapCall or other call trapping services

You could also subscribe to TrapCall, a service that finds out the caller ID of hidden or unknown numbers and blacklists unwanted calls. TrapCall offers three different services and their prices vary depending on the level of security you need.

Contact your phone company

You may also try to contact your phone company and see which services it offers.

Some might give you a pay-monthly plan that gets rid of marketing calls, or change your number if you are constantly getting ID-withheld phone calls. In some cases the phone company might also be able to identify the number behind hidden calls, but then the network provider can only give the number to the police if an investigation is under way.

However, in terms of blocking a hidden number, we are afraid that the majority of phone companies cannot do much about it.