diff --git a/java/client/src/org/openqa/selenium/firefox/FirefoxOptions.java b/java/client/src/org/openqa/selenium/firefox/FirefoxOptions.java
index 577564b49e5f3..44a1ae90f24e1 100644
--- a/java/client/src/org/openqa/selenium/firefox/FirefoxOptions.java
+++ b/java/client/src/org/openqa/selenium/firefox/FirefoxOptions.java
@@ -458,7 +458,7 @@ public Capabilities toCapabilities() {
   }
 
   private Capabilities toCapabilities(Capabilities source) {
-    HashMap<String, Object> caps = new HashMap<>();
+    HashMap<String, Object> caps = new HashMap<>(source.asMap());
 
     if (isLegacy()) {
       caps.put(FirefoxDriver.MARIONETTE, false);