diff --git a/src/main/java/seedu/address/model/person/Phone.java b/src/main/java/seedu/address/model/person/Phone.java
index 282a58ca3bb..e310598f32a 100644
--- a/src/main/java/seedu/address/model/person/Phone.java
+++ b/src/main/java/seedu/address/model/person/Phone.java
@@ -11,7 +11,8 @@ public class Phone {
 
 
     public static final String MESSAGE_CONSTRAINTS =
-            "Invalid Singapore phone number input. Enter a valid phone number that is more than 3 digits.";
+            "Invalid Singapore phone number input. "
+                    + "Enter a valid phone number that is 8 digits long and starts with 3, 6, 8 or 9.";
     public static final String VALIDATION_REGEX = "[3689]\\d{7}";
     public final String value;