What Is Call Blocking?
Call blocking is the feature that automatically blocks incoming calls from particular phone numbers. Calls from a number you have set are no longer put through to you, and the caller hears a recorded announcement such as "O-kake ni natta denwa bango e no tsuwa wa o-tsunagi dekimasen" (We cannot connect your call to the number you have dialled). Exactly what they hear varies with the carrier and your settings.
When a nuisance call or a sales call keeps coming back, blocking the number means you will never be troubled by that number again. It can all be done with the features already built into your smartphone, and there is no extra charge.
Blocking a Particular Number on an iPhone
Blocking from your call history
- Open the Phone app
- Tap the Recents tab
- Tap the "i" (information) button to the right of the number you want to block
- Scroll down the screen and tap Block this Caller
- Tap Block Contact to confirm
The whole thing takes less than ten seconds. Get into the habit of blocking a nuisance call there and then, as soon as you receive it.
Blocking from the Settings app
- Go to Settings, then Phone, then Blocked Contacts
- Tap Add New
- Choose the person you want to block from your contacts list
This method is convenient for blocking a number already saved in your contacts. To block a number that is no longer in your call history, save that number to your contacts first and then follow these steps.
Is there a limit on how many numbers an iPhone can block?
There is no limit on the number of entries in an iPhone's blocked list. You can add hundreds if you wish. Nuisance-call operators, however, work through several numbers in rotation, so blocking them one at a time is sometimes a losing battle. When that happens, make use of the feature for blocking all unknown numbers at once, described below.
Blocking a Particular Number on Android
Blocking from your call history
- Open the Phone app
- Tap the Recents tab
- Press and hold the number you want to block
- Tap Block number (or Block and report as spam)
The wording can differ with the model and the manufacturer. On a Samsung it appears as Block number / report as spam, on a Google Pixel simply as Block. On AQUOS and Xperia phones it is sometimes phrased as adding the number to a rejection list.
Spam filtering in the Google Phone app
Google's Phone app - installed as standard on the Google Pixel, and available for other Android handsets as well - can identify nuisance calls automatically. Go to Settings, then Spam and Call Screen, and turn on caller and spam ID, and a warning that the call is suspected spam appears whenever a known nuisance number rings you. Using a spam filter greatly reduces the effort of blocking numbers individually.
Blocking All Unknown Numbers at Once
Rather than naming particular numbers, you can reject every number that is not saved in your contacts. This is especially effective if nuisance calls reach you frequently.
On an iPhone
- Go to Settings, then Phone
- Turn on Silence Unknown Callers
Calls from numbers not saved in your contacts are silenced automatically and forwarded to voicemail. They still appear in your call history, so you can check them afterwards. Thanks to Siri's learning, numbers you have recently exchanged email or text messages with will still ring rather than being silenced.
On Android
- Open the Phone app
- Tap the menu at the top right, the three dots, then Settings
- Go to Blocked numbers and turn on Block unknown callers
On a Samsung handset the equivalent is found under the Phone app, then Settings, then Block numbers, then Block unknown or private numbers.
What Does the Blocked Caller Hear?
What a blocked caller hears differs with the carrier and the settings.
- iPhone, using the built-in feature: the phone rings once, then the call is forwarded to voicemail
- Docomo: "O-kake ni natta denwa bango e no tsuwa wa o-tsunagi dekimasen" (We cannot connect your call to the number you have dialled)
- au: "O-kake ni natta denwa o o-yobi shimashita ga o-de ni narimasen" (We rang the number you dialled, but there is no answer)
- SoftBank: "Kochira wa SoftBank desu. O-kake ni natta denwa bango e no tsuwa wa o-kyakusama no o-moushide ni yori o-tsunagi dekimasen" (This is SoftBank. At the customer's request, we cannot connect your call to the number you have dialled)
Whether the caller can tell for certain that they have been blocked varies from case to case. The iPhone's built-in feature merely forwards the call to voicemail, so to the caller it looks as though you simply did not answer. Carrier services play an announcement, so in those cases the caller may well work out that they have been blocked. For more, see our article on what a blocked caller hears.
Points to Watch When Blocking Calls
When they ring you from a different number
Nuisance-call operators often hold several numbers, and blocking one of them does not stop them calling from another. When that happens, use the feature that rejects all unknown numbers at once, or subscribe to your carrier's anti-nuisance-call service. Against operators who change numbers to get around call rejection, automatic blocking based on a database is the effective answer.
Important calls may be blocked as well
Set your phone to reject all unknown numbers and calls from hospitals, schools and other numbers not saved in your contacts are blocked too. When you are waiting for an important call, consider switching it off temporarily. Calls from delivery drivers are also blocked, so take care when you are expecting a parcel.
Text messages are blocked too
On an iPhone, text messages from a number on your blocked list are blocked as well. The same applies on Android. Where there is any chance that important information will arrive by text, check before you add the number to your blocked list.
Carrier Anti-Nuisance-Call Services
Where your phone's own settings cannot cope, the anti-nuisance-call services offered by the carriers are worth using as well.
- Docomo: Anshin Security, 220 yen a month - automatic identification of and warnings about nuisance calls
- au: Nuisance Message and Call Block, 330 yen a month - automatic blocking based on a database
- SoftBank: Nuisance Call Block, 330 yen a month - automatic identification and blocking of nuisance calls
These services check calls against a database of nuisance numbers and warn you or block the call automatically, which saves you the effort of registering numbers one by one. Because the blocking happens at the network level, it has no effect on your phone's battery either. For anybody who receives nuisance calls frequently, a few hundred yen a month buys a considerable reduction in aggravation.
Combine Blocking With Other Measures
Call blocking is the foundation of dealing with nuisance calls, but on its own it is sometimes not enough. Combining it with the following makes it more effective still.
- Install a nuisance-call app: these display warnings as the call comes in, such as possibly a sales call, or reported as fraud
- Do not answer numbers you do not know: send them to voicemail, and anybody with genuine business will leave a message
- Search the number before calling back: when you find a missed call, search for the number on this site before you return it
- Tell sales callers not to call you again: under the Act on Specified Commercial Transactions, further solicitation after you have refused is prohibited
Summary
Nuisance calls can be dealt with by blocking them. Start by blocking the number from your call history. If they still reach you from a different number, make use of the option to reject all unknown numbers, or of your carrier's service. Combining several measures will cut the nuisance calls that get through to you dramatically.