diff --git a/config.json b/config.json
index caa7cf7ac2..651a78da97 100644
--- a/config.json
+++ b/config.json
@@ -821,7 +821,12 @@
         "name": "Phone Number",
         "uuid": "82775adb-eabe-4d44-91f5-4080b8834a4a",
         "practices": [],
-        "prerequisites": [],
+        "prerequisites": [
+          "strings",
+          "comparison",
+          "conditionals",
+          "regular-expressions"
+        ],
         "difficulty": 3,
         "topics": ["parsing", "transforming"]
       },