I've been getting tons of spam calls lately—like, multiple calls per day. My carrier suggests that I change my number, but I don't want to do that. Is there anything else I can do?
Signed,
Endless Ringing
We've posted this once before, but we've gotten this question a few times lately, so we've updated our guide with modern information to help out those still getting unwanted calls. Enjoy!
Dear Endless,
You actually have quite a few options depending on the type of phone you're using. Let's take a look at what some of the more popular phones have built in.

Block Calls on Android

Android users have a number of apps available in the Play Store that can block calls. Previously mentioned Call Filter is definitely the most popular option, and it's completely free. DroidBlock will also do the trick of Call Filter doesn't.
Success with call-blocking apps tends to vary and they're not always 100% effective. If you want to avoid apps you may have another option built into Android. Some Android phones can send calls directly to voicemail, which you can enable by editing the contact information containing the number you want to block.
Some other phones (like many Samsung phones) may have call blocking options built-in, but it varies from phone to phone. Google your phone to see if it has any call blocking features out-of-the-box.

Block Calls on a Jailbroken iPhone

The iPhone doesn't allow apps that block calls, nor does it have a true call blocking feature built in. However, if you've jailbroken your phone (which is super easy to do), you can purchaseiBlackList through Cydia.
If you don't want to jailbreak, check out some of the solutions below instead.

Block Calls on Any Phone

The following methods will work no matter what phone you have:

Google Voice

One of the best ways to block calls is to use Google Voice. If you don't have a Google Voice account and you live in the US, you can sign up hereBlocking calls with Google Voice is pretty simple: you have the option of sending them directly to voicemail, treating all their calls as spam, or blocking them entirely. Here's how blocking works:
  1. Log in to your Google Voice account.
  2. Find the call you want to block (or the voicemail that resulted from it).
  3. Select the checkbox next to the call or voicemail.
  4. Click the "more" link underneath the call.
  5. Select "Block Caller."
The best part is, you don't need change your number to do this. You just need to use Google Voice for voicemail, as reader Grays explains:
I do not use Google Voice normally as I do not give out my GV number; instead I use it as my Voicemail. People call my normal Sprint number and I have it conditional call forwarded (conditional means its only forwards when its busy or I do not answer) to my GV number. This is done on Sprints network by using *28. (Ed. note: You can see instructions on how to do this on any carrier from Google Voice's settings).
So now when someone calls my Sprint phone and I don't answer, it rolls to Google Voice as my voicemail and from there I can block calls. In this scenario it still rings to me but if I don't answer and I have them blocked they get a nice "this number has been disconnected" message. It only takes them one or two times before they then quit calling thinking the number is disconnected. It's a great alternative and I get to keep my cell number.

Silence the Call

Another option is to just silence the call. While it isn't technically a call-blocking method, the result is pretty much the same. Just install a silent ringtone on your phone, then attach it to numbers you don't want to answer and your phone will stay silent when they call.

Contact Your Carrier

Most carriers have a means of blocking calls even if they don't realize it. It usually costs money and it usually falls under the header of Parental Controls but it works just the same. AT&T uses a feature called Smart Controls to get the job done, and charges $5/month for the service. Verizon has a free call blocking service that can block five callers at a time, or a $5/month option called Usage Controls with more features. With T-Mobile, doesn't have an official call blocking service, but some users say you can call 611 and customer service will help you block any particular number. Sprint users can manage blocked calls from their My Sprint account settings.
If you don't like your carrier options, TrapCall (our previous post) is an inexpensive service that'll not only block calls, but can even unmask numbers that appear as "blocked" when they call you. It offers some other options, such as voicemail transcription at an additional cost, but $5 a month will get you the basic features you're looking for. Thanks sleepmanager for the tip!

While there's no obvious one-size-fits-all solution, you've got plenty of options for blocking unwanted calls. You just have to find the option that best fits your needs.