diff --git a/src/main/java/org/apache/commons/lang3/CharSequenceUtils.java b/src/main/java/org/apache/commons/lang3/CharSequenceUtils.java
index fdb91220b..0dace41e5 100644
--- a/src/main/java/org/apache/commons/lang3/CharSequenceUtils.java
+++ b/src/main/java/org/apache/commons/lang3/CharSequenceUtils.java
@@ -134,6 +134,13 @@ public class CharSequenceUtils {
      * @return the index where the search sequence was found
      */
     static int indexOf(final CharSequence cs, final CharSequence searchChar, final int start) {
+        if (cs instanceof String) {
+            return ((String) cs).indexOf(searchChar.toString(), start);
+        } else if (cs instanceof StringBuilder) {
+            return ((StringBuilder) cs).indexOf(searchChar.toString(), start);
+        } else if (cs instanceof StringBuffer) {
+            return ((StringBuffer) cs).indexOf(searchChar.toString(), start);
+        }
         return cs.toString().indexOf(searchChar.toString(), start);
 //        if (cs instanceof String && searchChar instanceof String) {
 //            // TODO: Do we assume searchChar is usually relatively small;
@@ -218,6 +225,13 @@ public class CharSequenceUtils {
      * @return the index where the search sequence was found
      */
     static int lastIndexOf(final CharSequence cs, final CharSequence searchChar, final int start) {
+        if (cs instanceof String) {
+            return ((String) cs).lastIndexOf((String) searchChar, start);
+        } else if (cs instanceof StringBuilder) {
+            return ((StringBuilder) cs).lastIndexOf((String) searchChar, start);
+        } else if (cs instanceof StringBuffer) {
+            return ((StringBuffer) cs).lastIndexOf((String) searchChar, start);
+        }
         return cs.toString().lastIndexOf(searchChar.toString(), start);
 //        if (cs instanceof String && searchChar instanceof String) {
 //            // TODO: Do we assume searchChar is usually relatively small;