diff --git a/README.md b/README.md
index 4a4938ed..2fd6b7f0 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,9 @@ For all Swift code (3 and 4 above) - they are built with **SPM**
 
 ## Developer Workflow
 
+### Swift Toolchain
+This project may require Swift toolchain builds which are more recent than the latest released version. For best results, find the release tag used by the [GitHub Actions build workflow](.github/actions/windows-build/action.yml) and download the corresponding toolchain build from [swift-build releases](https://github.com/thebrowsercompany/swift-build/releases).
+
 ### Initial Setup
 
 Initialize submodules: