diff --git a/src/Outcome.php b/src/Outcome.php
index d964ab7..a7964ec 100644
--- a/src/Outcome.php
+++ b/src/Outcome.php
@@ -86,6 +86,20 @@ class Outcome
      */
     public ?string $comment = null;
 
+    /**
+     * Date submission started.
+     *
+     * @var DateTime|null $submissionStarted
+     */
+    public ?\DateTime $submissionStarted = null;
+
+    /**
+     * Date submission completed.
+     *
+     * @var DateTime|null $submissionCompleted
+     */
+    public ?\DateTime $submissionCompleted = null;
+
     /**
      * Outcome data source value.
      *
diff --git a/src/Service/Score.php b/src/Service/Score.php
index 6b68b8d..6f119ae 100644
--- a/src/Service/Score.php
+++ b/src/Service/Score.php
@@ -67,6 +67,15 @@ public function submit(Outcome $ltiOutcome, User $user): bool
             $json['scoreGiven'] = $score;
             $json['scoreMaximum'] = $ltiOutcome->getPointsPossible();
         }
+        if (!empty($ltiOutcome->submissionStarted) || !empty($ltiOutcome->submissionCompleted)) {
+            $json['submission'] = [];
+            if (!empty($ltiOutcome->submissionStarted)) {
+                $json['submission']['startedAt'] = date_format($ltiOutcome->submissionStarted, 'Y-m-d\TH:i:s.uP');
+            }
+            if (!empty($ltiOutcome->submissionStarted)) {
+                $json['submission']['submittedAt'] = date_format($ltiOutcome->submissionCompleted, 'Y-m-d\TH:i:s.uP');
+            }
+        }
         $data = json_encode($json);
         $http = $this->send('POST', null, $data);