Signs someone else may be using your Wi-Fi

Internet that is slower than usual at odd hours, a router activity light that blinks constantly when your own devices are idle, or a monthly data cap that runs out early can all point to an extra user. Unknown names in the connected-devices list are the clearest sign.

Most of the time the explanation is innocent: a smart plug, a TV, a guest phone that remembered your password, or a device that renewed its address with a new name.

Check the list before changing anything, so you know what is really connected.

Check the connected-devices list on your router

Open a browser and go to your router address, often 192.168.1.1, 192.168.0.1 or 10.0.0.1. Sign in with the admin password printed on the router or set during installation. Look for Connected devices, Attached devices, DHCP clients or Device list.

Many routers and mesh systems also have a phone app that shows the same list with friendlier names and lets you pause or block a device with one tap.

Each entry usually shows a device name, a private IP address, a MAC address and whether it uses Wi-Fi or a cable.

  1. Find the router address (Default Gateway).
  2. Sign in to the router admin page or app.
  3. Open the connected-devices list.
  4. Count the devices and compare with what you own.

How to identify unknown devices

Turn off or disconnect your own devices one at a time and watch which entries disappear. The first half of a MAC address identifies the manufacturer, so a lookup can tell you that an unknown entry was made by a TV, printer or phone brand you own.

Remember that modern phones use a randomised private MAC address for each network, so the same phone can look like a new device after a reset. Name every device you recognise in the router so new ones stand out next time.

Example connected-devices list
Name             IP             MAC prefix   Type
Anna-iPhone      192.168.1.21   Apple        Wi-Fi
LivingRoom-TV    192.168.1.34   Samsung      Wi-Fi
unknown          192.168.1.57   Espressif    Wi-Fi   <- smart plug chip
DESKTOP-7Q2      192.168.1.10   Intel        Ethernet

How to remove someone from your Wi-Fi

The quickest fix is to block the device in the router, often called MAC filtering, access control or pause. Because MAC addresses can be changed, the only permanent fix is to change the Wi-Fi password. Every device must then reconnect with the new password, and anyone who does not know it is locked out.

While you are in the settings, switch to WPA3 or WPA2-AES security, turn off WPS, which can be easier to break, and change the router admin password if it is still the default.

For visitors, create a guest network with its own password. Guests get internet access without seeing your computers, printers or storage.

Keep your network private

Use a long, unique Wi-Fi password of at least 12 characters. Update the router firmware or enable automatic updates. Replace routers that no longer receive security updates.

Review the device list every few months, especially after parties, renovations or moving in with new people. Turn off remote administration unless you need it.

If you think someone has accessed your devices, not just your Wi-Fi, change important passwords from a trusted device and turn on two-factor authentication.