What Split Tunneling Does
Split tunneling divides your internet traffic into two streams: traffic that goes through the VPN tunnel (encrypted, using the VPN's IP address) and traffic that goes directly to the internet (unencrypted, using your real IP). You configure which apps or domains use which stream.
When Split Tunneling is Useful
The most common use case is streaming. When your VPN routes all traffic, streaming services that detect your VPN server's IP block access. With split tunneling, you can route your browser or streaming app through your real connection while routing everything else through the VPN. This lets you access geo-restricted content that works without a VPN while keeping other traffic private.
A second use case is performance. VPN tunnels add latency. For online gaming, video calls, or latency-sensitive applications, routing those through your real connection while protecting other traffic gives you the best of both.
The third use case is local network access. When your VPN is fully active, you typically cannot access devices on your local network (printers, NAS drives, other computers) because the VPN routes all traffic away from the local subnet. Split tunneling can exclude local network traffic from the VPN, restoring access.
The Security Trade-Off
Split tunneling reduces your security surface. Any traffic routed outside the VPN is unprotected: your ISP can see it, any network you are on can log it, and your real IP is visible to the destination server. This is acceptable for streaming services you do not care about keeping private. It is not acceptable for traffic you specifically chose a VPN to protect.
The configuration question is: do you know which traffic is sensitive and which is not? If yes, split tunneling is a reasonable trade-off. If no, routing everything through the VPN is safer even at the cost of speed.
VPNs with Good Split Tunneling Implementations
ExpressVPN calls their implementation split tunneling and offers both app-based (route specific apps outside VPN) and inverse mode (route everything outside VPN except specified apps). NordVPN offers app-based split tunneling on Windows and Android. Mullvad offers split tunneling but recommends against it for privacy-critical use cases, which reflects their security-first positioning honestly.