diff --git a/eng/ci/code-mirror.yml b/eng/ci/code-mirror.yml
index 0a2196b95..40f2d2a0f 100644
--- a/eng/ci/code-mirror.yml
+++ b/eng/ci/code-mirror.yml
@@ -5,6 +5,7 @@ trigger:
     # Keep this set limited as appropriate (don't mirror individual user branches).
     - main
     - dev
+    - v3.x
 
 resources:
   repositories:
diff --git a/eng/ci/official-build.yml b/eng/ci/official-build.yml
index e7a871026..858ca3518 100644
--- a/eng/ci/official-build.yml
+++ b/eng/ci/official-build.yml
@@ -7,6 +7,7 @@ trigger:
         include:
             - main
             - dev
+            - v3.x
 
 # CI only, does not trigger on PRs.
 pr: none