There is a third party Wireguard implementation for Windows: https://tunsafe.com/
However the Wireguard creator has some reservations about this third party client:
>We'll have an official Windows client coming out shortly
>9 months ago
>For those who are after Windows clients, the WireGuard project will hopefully have one quite soon,
>4 months ago
This is the problem.
Apologies if you're a paying supporter, but then you would already know what to expect and when. https://www.patreon.com/zx2c4
I'm personally happy to wait for the quality official client with upstream support (even though I gave a try to TunSafe without expectation to use it in the long term).
An independent implementation of Wireguard is a good thing, but zx2c4 apparently doesn't want that. I can't explain the zealous fight against it otherwise.
TunSafe's author Ludde also made µtorrent which he so often says. But depending on the version you have it's either good or infested with adware. Although the later one is not his fault anymore, I still wouldn't mention it without the version number that was still good.
[1]: https://github.com/StreisandEffect/streisand