The best open source alternative to VPN is Tor, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 100 alternatives to VPN and many of them is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to VPN are OpenVPN (Freemium, Open Source), ProtonVPN (Freemium, Open Source), WireGuard (Free, Open Source) and I2P (Free, Open Source).
Bitmask is an EXPERIMENTAL open source application to provide easy and secure encrypted communication. You can choose among several different service providers or start your own. Currently, it supports encrypted internet (VPN) and encrypted email.
RiseupVPN service for censorship circumvention, location anonymization and traffic encryption. To make this possible, it sends all your internet traffic through an encrypted connection to riseup.net, where it then goes out onto the public internet.
Protect your web history, feel safer on public Wi-Fi, and limit ad tracking by increasing the security of your network connection. Mozilla VPN is currently offered in the US, the UK, Canada, New Zealand, Singapore and Malaysia.
sshuttle: where transparent proxy meets VPN meets ssh sshuttle is the only program that solves the following common case: Your client machine (or router) is Linux, FreeBSD, or MacOS. You have access to a remote network via ssh.