Your home Wi-Fi suddenly becomes slow even though you're not downloading anything. Videos start buffering, websites take longer to open, and online meetings begin freezing. While the internet provider may sometimes be responsible, there is another possibility—an unknown device could be connected to your Wi-Fi network.
An unauthorized connection doesn't just consume bandwidth. Depending on how your home network and devices are configured, poor Wi-Fi security can also create unnecessary privacy and security risks.
Fortunately, there are several ways to check whether unfamiliar devices are connected and strengthen your network.
1. Internet Suddenly Becomes Slower
An unexpected drop in internet speed can be one of the first things you notice.
If another device is streaming high-resolution videos, downloading large files or performing other bandwidth-heavy activities, your connection may slow down.
However, slow Wi-Fi alone doesn't prove that someone has accessed your network. Network congestion, router problems, weak signals and issues at the internet provider can produce similar symptoms.
2. You See Devices You Don't Recognize
Many modern routers allow users to view devices currently connected to the network.
Open your router's management interface or its official mobile app and look for sections such as Connected Devices, Device List, Clients or similar wording.
You may see smartphones, televisions, laptops, security cameras, smart speakers and other connected devices.
If a device appears that you cannot identify, investigate further before assuming it belongs to an intruder. Some devices may appear under unfamiliar manufacturer names or technical identifiers.
3. Router Lights Keep Flashing When Nobody Is Online
Some routers have indicator lights that flash when data is being transmitted.
If all known devices are disconnected but activity continues, there may still be another connected device.
However, smart-home products, security cameras, televisions and other appliances can remain connected even when you aren't actively using them, so flashing lights aren't definitive proof of unauthorized access.
4. Your Data Usage Has Increased Unexpectedly
If your broadband plan or internet provider allows you to monitor data consumption, an unexplained increase may be worth investigating.
Heavy streaming, gaming or downloads from another connected device can increase overall usage.
Before becoming concerned, check whether your own devices have recently downloaded operating-system updates, backed up photos or videos to the cloud, or installed large games.
5. Router Settings Have Changed
Unexpected changes to your network name, Wi-Fi password, DNS settings or router administrator credentials deserve attention.
Such changes could indicate that someone gained access to the router's management settings.
If you suspect unauthorized changes, reset the router securely if necessary and configure it again using strong, unique credentials. Follow the router manufacturer's official instructions when performing a factory reset.
6. Unknown Devices Keep Returning
Removing or blocking an unfamiliar device may solve the immediate problem, but if unknown connections repeatedly appear, your Wi-Fi password or router security may need attention.
Changing the Wi-Fi password can disconnect devices that previously had access.
Remember that after changing the password, you'll need to reconnect your legitimate phones, laptops, TVs and smart-home devices using the new credentials.
What Should You Do If You Find an Unknown Device?
Start by identifying all the devices in your home. Don't immediately block something simply because its displayed name looks unfamiliar.
If you're confident a device doesn't belong to you or anyone authorized to use the network, you can take several precautions:
- Change your Wi-Fi password.
- Use a long, unique password that isn't reused elsewhere.
- Choose WPA2 or WPA3 security if supported by your router and devices.
- Change the router's administrator password if it is still using a default or weak credential.
- Install router firmware updates when available from the manufacturer.
- Disable features you don't use, especially remote router administration.
After changing the Wi-Fi password, reconnect only the devices you recognize.
Don't Share Your Main Wi-Fi Password With Everyone
If visitors regularly need internet access, check whether your router supports a guest network.
A guest network can provide internet access without necessarily placing visitors' devices on the same primary network as your computers and other equipment, depending on the router's configuration.
