The 4 Best Free Antivirus Apps for Android Phones

Avira’s Antivirus Security app for Android does what all antivirus apps should do: Automatically scans apps for malware, checks for threats in external storage devices, shows which apps have access to your private information, and is extremely easy to use.

Avira can scan each time you disconnect from a computer as well as start scheduled scans once a day, every day. If that isn't enough for you, you can always start a manual scan whenever you want to check for malware like adware, riskware, ransomware, and potentially unwanted programs.

When threats are found, you'll be alerted of the threat type (riskware, PUP, etc.) and will have the option to ignore them or delete them on the spot.

Here are some other things the Avira Antivirus Security app is capable of:

• Updated apps are re-scanned when they're finished updating, to ensure that any new files aren't infected
• You get to define whether files and/or apps are scanned
• The app can be set up to only show notifications when threats are found, which is really handy so you aren't bombarded with messages each time Avira finds your mobile device clean
• There's also an anti-theft tool that lets you find your device remotely, or even lock it or wipe it, via your Avira Connect account
• When checking which apps have privileged access to your information (as well as what access they have), they are categorized as being high risk, medium risk, or low risk but you can always "trust" any of them to remove them from being labeled as a risk
• An Activity section shows a history of what Avira has been doing and what it finds; it's easy to sift through since threats are marked in red
• Overcharge Protection can remind you to unplug the device when it’s fully charged
• You can use the blacklist feature to prevent certain phone numbers from reaching you; it works with any number you enter but you can also blacklist all private numbers and/or all callers that appear as unknown

This free version of Avira Antivirus Security is very much like the professional edition you can buy except that the pro version doesn’t contain ads, will update its definitions every hour, and supports the secure browsing feature that helps your device stay clean when browsing the web, downloading files, and shopping online.

Security Master (previously known as CM Security) is an incredibly popular app that integrates an antivirus scanner with a suite of other tools.

This app checks for viruses, malicious ads, Trojans, vulnerabilities, hacking tools, and more.

It not only makes checking for all sorts of malware just one tap away, but also provides various privacy, security, and performance related tools to keep your phone in tip-top shape.

Here's a list of other features found in Security Master:

• Auto-scans for malware as apps are installing, and automatically blocks any threats
• Lets you perform a malware scan at any time
• Can connect you to the internet through a VPN that provides 200 MB of free data every day; it can even be set up to only turn on when you're using apps with security risks
• A cleaner helps restore storage used by unnecessary things like caches and junk files 
• Includes various privacy protection tools like a password to open any or all of your apps
• An intruder selfie option takes a photo of anyone who incorrectly enters a password
• Push notifications can be censored for specific apps to provide privacy on incoming alerts
• A safe browsing tool makes it simple to delete your browsing history after using the browser built-in to Security Master
• The app can identify the phone's temperature and report if it's normal or not; it gives a list of apps that are currently using system resources and lets you shut them down to cool off the phone
• A power usage analyzer shows which apps can be hibernated to save battery, and even estimates how much battery life you'll save by shutting those apps down (which you can do with one tap)
• The Wi-Fi Security tool easily shuts down apps that are using the most bandwidth; it also tests the internet speed and the security of the network you're on as well as has an option to remove the ability for your phone to access insecure networks (there's also a way to find public hotspots with this app)
• Use the Caller ID & Blocking section to block private numbers, numbers not in your address book, any number you choose, international numbers, numbers that start with at least two numbers of your choosing (e.g. block 800* numbers), and/or all calls within a select time period

Security Master is clearly a... master of security. If that's what you're after, then great. If not, you might find all these extra tools to just be in the way.

However, it's important to note that regardless of all these options and capabilities in Security Master, nearly everything is accessible with a large button, so most things are just one or two taps away and are categorized in their own areas.

The two already mentioned antivirus apps for Android are clearly stuffed with features and that's where Bitdefender's AV app differs: it's completely free from clutter and includes only an antivirus tool.

The only manual thing you can do with Bitdefender is to start with a scan and choose whether or not to include an SD card in the check against viruses and other threats. 

Once the full scan has completed, you'll be protected against any new app installs automatically so that they're blocked before they can do any damage.

If a threat is found, you'll be taken into the results screen where you can easily uninstall the culprits.

Bitdefender is said to be super light on resources since it doesn't download and store virus signatures on the device, but instead uses "in-the-cloud services to check online for the latest safeguards to outbreaks."

The only drawback to Bitdefender Antivirus Free is when you compare it to Bitdefender's not-free Mobile Security & Antivirus app, which checks your browsing habits in real-time and can lock down or wipe your phone if it's stolen, which are pretty handy features.