IKEv2 is one of three or four protocols a consumer VPN app will offer, and the one most likely to be selected automatically on a phone. A protocol is the set of rules for building and maintaining the encrypted tunnel: it decides how fast the connection is, how gracefully it survives a network change, and how easily a restrictive network can spot and block it. IKEv2's particular strength is the second of those.
Why it is the phone protocol
IKEv2 pairs with a component called MOBIKE that lets an established tunnel survive a change of network. Walk out of the house and a phone moves from wifi to mobile data; with most protocols the tunnel drops and reconnects, and with IKEv2 it usually carries on. On a device that changes network several times an hour, that is the difference between a VPN you leave on and one you keep switching off. It is also built into iOS and Android at the operating-system level, so it can be configured without the provider's app.
How it compares with WireGuard and OpenVPN
WireGuard is newer, has far less code, and is generally the fastest of the three; most providers now default to it or to their own variant of it on desktop. OpenVPN is the oldest, the slowest, and the most thoroughly audited, and it is the easiest to disguise as ordinary web traffic because it can run over TCP on port 443. IKEv2 sits between them: fast, stable across network changes, and the easiest of the three for a restrictive network to identify and block, because it uses recognisable UDP ports.
When to choose it deliberately
Leave the protocol on automatic unless you have a specific problem. Choose IKEv2 when a mobile connection keeps dropping the tunnel as you move around. Choose WireGuard when you want speed on a fixed connection. Choose OpenVPN over TCP 443 when a network is blocking the VPN entirely, which is the situation the protocol menu exists for and the one case where automatic selection will not rescue you.
What the protocol does not decide
The protocol is not the privacy policy. Which of these a provider offers, and whether it keeps records of your connections, are unrelated questions: every provider in this index offers a similar protocol menu, and what separates them is what they publish about logging and what they charge. The no-logs page each one maintains is linked from its profile here.
Questions people ask about ikev2 vpn
Is IKEv2 secure?
Yes, when configured with modern ciphers, which is what every provider in this index does. It is a mature open standard rather than a proprietary one.
Which protocol is fastest?
Usually WireGuard, on most connections and most hardware. IKEv2 is close behind and OpenVPN is typically the slowest.
Why does my app keep switching protocols?
Automatic selection tries the protocol most likely to connect on the network you are on. It is usually the right behaviour and it is why most people never open the menu.