diff --git a/icu4c/source/common/ucnv_io.c b/icu4c/source/common/ucnv_io.c
index cb53e203946..937d4f7f906 100644
--- a/icu4c/source/common/ucnv_io.c
+++ b/icu4c/source/common/ucnv_io.c
@@ -553,7 +553,7 @@ findTaggedConverterNum(const char *alias, const char *standard, UErrorCode *pErr
             for (idx = convStart; idx < convLimit; idx++) {
                 listOffset = gTaggedAliasArray[idx];
                 if (listOffset && isAliasInList(alias, listOffset)) {
-                    return convNum;
+                    return idx-convStart;
                 }
             }
             /* The standard doesn't know about the alias */
@@ -933,6 +933,7 @@ ucnv_openAllNames(UErrorCode *pErrorCode) {
     return myEnum;
 }
 
+#ifdef ICU_UNICODECONVERTER_USE_DEPRECATES
 U_CFUNC void
 ucnv_io_fillAvailableConverters(const char **aliases, UErrorCode *pErrorCode) {
     if (haveAvailableConverterList(pErrorCode)) {
@@ -942,6 +943,7 @@ ucnv_io_fillAvailableConverters(const char **aliases, UErrorCode *pErrorCode) {
         }
     }
 }
+#endif
 
 U_CFUNC uint16_t
 ucnv_io_countAvailableAliases(UErrorCode *pErrorCode) {
diff --git a/icu4c/source/common/ucnv_io.h b/icu4c/source/common/ucnv_io.h
index 8a866425852..a3a7e5a6503 100644
--- a/icu4c/source/common/ucnv_io.h
+++ b/icu4c/source/common/ucnv_io.h
@@ -106,6 +106,7 @@ ucnv_io_countAvailableConverters(UErrorCode *pErrorCode);
 U_CFUNC const char *
 ucnv_io_getAvailableConverter(uint16_t n, UErrorCode *pErrorCode);
 
+#ifdef ICU_UNICODECONVERTER_USE_DEPRECATES
 /**
  * Fill an array const char *aliases[ucnv_io_countAvailableConverters()]
  * with pointers to all converter names in mixed-case.
@@ -114,6 +115,7 @@ ucnv_io_getAvailableConverter(uint16_t n, UErrorCode *pErrorCode);
  */
 U_CFUNC void
 ucnv_io_fillAvailableConverters(const char **aliases, UErrorCode *pErrorCode);
+#endif
 
 /**
  * Return the (n)th converter name in mixed case, or NULL