Public WiFi networks are fundamentally different from your home network in one important way: every other device on the same network is a potential adversary. The person at the next table, the hotel guest down the hall, or someone sitting in a car outside a coffee shop can run network monitoring tools that capture unencrypted traffic from every device on the same access point.
This is not a theoretical risk. The attack is called a man-in-the-middle attack, and the tools to execute it are freely available and require minimal technical knowledge. When you connect to an open WiFi network and browse without a VPN, any unencrypted HTTP traffic you send is visible to anyone on the same network who is looking.
HTTPS reduces this risk significantly. When you visit a site over HTTPS, the connection is encrypted between your browser and the server. A network eavesdropper can see that you connected to a server at a particular IP address but cannot read the content of the connection. Most modern websites use HTTPS, and browsers now warn you prominently when they do not.
So why does a VPN still matter? Several reasons. First, not every app on your device uses HTTPS. Email clients, navigation apps, background sync services, and older applications may send unencrypted traffic you are not aware of. A VPN encrypts all traffic from your device at the network level, regardless of which application generated it.
Second, a VPN hides which sites you are connecting to. Even over HTTPS, the server's IP address is visible. DNS queries, which translate domain names into IP addresses, may also be visible unless you use a secure DNS service. A VPN routes all your traffic through an encrypted tunnel, hiding both your DNS queries and your connection destinations from anyone monitoring the local network.
For travel and public WiFi use specifically, a VPN with a reliable kill switch is the right choice. The brief moment when you connect to a new network and the VPN is establishing its connection is a window when traffic can leak. A kill switch prevents that. For advice on VPN kill switches, see our explanation at /vpn-kill-switch-explained-2026.