diff --git a/dashboard/builders.go b/dashboard/builders.go
index dbae57c..bd0f943 100644
--- a/dashboard/builders.go
+++ b/dashboard/builders.go
@@ -25,8 +25,9 @@
 // syntax entirely. This is a first draft.
 var slowBotAliases = map[string]string{
 	// Known missing builders:
-	"darwin-arm": "", // TODO(golang.org/issue/37611): Remove once port is removed.
-	"ios-amd64":  "", // There is no builder for the iOS Simulator. See issues 42100 and 42177.
+	"darwin-arm":    "", // TODO(golang.org/issue/37611): Remove once port is removed.
+	"ios-amd64":     "", // There is no builder for the iOS Simulator. See issues 42100 and 42177.
+	"windows-arm64": "", // TODO(golang.org/issue/42604): Add builder for windows/arm64.
 
 	"386":            "linux-386",
 	"aix":            "aix-ppc64",
diff --git a/dashboard/builders_test.go b/dashboard/builders_test.go
index d86db26..ed11532 100644
--- a/dashboard/builders_test.go
+++ b/dashboard/builders_test.go
@@ -830,8 +830,9 @@
 	ports := strings.Fields(string(out))
 
 	done := map[string]bool{}
-	done["darwin-arm"] = true   // TODO: Remove when Go 1.16 is out and Go 1.14 becomes unsupported.
-	done["darwin-arm64"] = true // TODO(golang.org/issue/39782): Add builder for darwin/arm64.
+	done["darwin-arm"] = true    // TODO: Remove when Go 1.16 is out and Go 1.14 becomes unsupported.
+	done["darwin-arm64"] = true  // TODO(golang.org/issue/39782): Add builder for darwin/arm64.
+	done["windows-arm64"] = true // TODO(golang.org/issue/42604): Add builder for windows/arm64.
 	check := func(goos, goarch string) {
 		if goos == "android" || goos == "ios" {
 			// TODO(golang.org/issue/25963): support