diff --git a/icu4c/source/common/ucnv_io.c b/icu4c/source/common/ucnv_io.c
index f3873ee8c1d..bab3ed7978e 100644
--- a/icu4c/source/common/ucnv_io.c
+++ b/icu4c/source/common/ucnv_io.c
@@ -83,6 +83,9 @@ static const char DATA_TYPE[] = "dat";
 static UDataMemory *aliasData=NULL;
 static const uint16_t *aliasTable=NULL;
 
+static const char **availableConverters = NULL;
+static uint16_t availableConverterCount = 0;
+
 static const uint16_t *converterTable = NULL;
 static const uint16_t *tagTable = NULL;
 
@@ -167,8 +170,15 @@ ucnv_io_cleanup()
 {
     if (aliasData) {
         udata_close(aliasData);
+        aliasData = NULL;
     }
 
+    if (availableConverters) {
+        uprv_free((char **)availableConverters);
+        availableConverters = NULL;
+    }
+    availableConverterCount = 0;
+
     aliasData = NULL;
     aliasTable = NULL;
 
@@ -396,10 +406,42 @@ ucnv_getStandardName(const char *alias, const char *standard, UErrorCode *pError
    return NULL;
 }
 
+static void ucnv_io_loadAvailableConverterList(void) {
+    uint16_t idx = 0;
+    uint16_t localConverterCount = 0;
+    UErrorCode status;
+    char *converterName;
+
+    /* We can't have more than "*converterTable" converters to open */
+    char **localConverterList = (char **) uprv_malloc(*converterTable * sizeof(char*));
+
+    for (; idx < *converterTable; idx++) {
+        status = U_ZERO_ERROR;
+        converterName = (char *)aliasTable+converterTable[1+2*idx];
+        ucnv_close(ucnv_open(converterName, &status));
+        if (U_SUCCESS(status)) {
+            localConverterList[localConverterCount++] = converterName;
+        }
+    }
+
+    umtx_lock(NULL);
+    if (availableConverters == NULL) {
+        availableConverters = localConverterList;
+        availableConverterCount = localConverterCount;
+    }
+    else {
+        uprv_free(localConverterList);
+    }
+    umtx_unlock(NULL);
+}
+
 U_CFUNC uint16_t
 ucnv_io_countAvailableConverters(UErrorCode *pErrorCode) {
     if(haveAliasData(pErrorCode)) {
-        return *converterTable;
+        if (availableConverters == NULL) {
+            ucnv_io_loadAvailableConverterList();
+        }
+        return availableConverterCount;
     }
     return 0;
 }
@@ -407,9 +449,11 @@ ucnv_io_countAvailableConverters(UErrorCode *pErrorCode) {
 U_CFUNC const char *
 ucnv_io_getAvailableConverter(uint16_t n, UErrorCode *pErrorCode) {
     if(haveAliasData(pErrorCode)) {
-        const uint16_t *p=converterTable;
-        if(n<*p) {
-            return (const char *)aliasTable+p[1+2*n];
+        if (availableConverters == NULL) {
+            ucnv_io_loadAvailableConverterList();
+        }
+        if(n < availableConverterCount) {
+            return availableConverters[n];
         }
     }
     return NULL;