diff --git a/eng/prebuilts/mobile/icudt_hybrid.dat b/eng/prebuilts/mobile/icudt_hybrid.dat
index 8f56b66d49b..36a78e7c75d 100644
Binary files a/eng/prebuilts/mobile/icudt_hybrid.dat and b/eng/prebuilts/mobile/icudt_hybrid.dat differ
diff --git a/icu-filters/icudt_hg_mobile.json b/icu-filters/icudt_hg_mobile.json
index 027cf02f1c4..5a4c030fbb3 100644
--- a/icu-filters/icudt_hg_mobile.json
+++ b/icu-filters/icudt_hg_mobile.json
@@ -231,37 +231,10 @@
         "brkitr_rules": {
             "whitelist": ["char"]
         },
-        "coll_tree": "exclude"
+        "coll_tree": "exclude",
+        "locales_tree": "exclude"
     },
     "resourceFilters": [
-        {
-            "categories": ["locales_tree"],
-            "rules": [
-                "-/characterLabel",
-                "-/measurementSystemNames",
-                "-/listPattern",
-                "-/fields",
-                "-/delimiters",
-                "-/Ellipsis",
-                "-/NumberElements/latn/miscPatterns",
-                "-/NumberElements/latn/patternsLong",
-                "-/NumberElements/latn/patternsShort",
-                "-/NumberElements/*/patternsLong",
-                "-/NumberElements/*/patternsShort",
-                "-/NumberElements/minimalPairs",
-                "-/NumberElements/*/symbols",
-                "-/calendar/Gregorian/AmPmMarkers",
-                "-/calendar/Gregorian/AmPmMarkersAbbr",
-                "-/calendar/Gregorian/AmPmMarkersNarrow",
-                "-/parse",
-                "-/AuxExemplarCharacters",
-                "-/ExemplarCharacters",
-                "-/ExemplarCharactersIndex",
-                "-/ExemplarCharactersNumbers",
-                "-/ExemplarCharactersPunctuation",
-                "-/MoreInformation"
-            ]
-        },
         {
             "categories": ["misc"],
             "files": {
diff --git a/icu/icu4c/source/common/uloc.cpp b/icu/icu4c/source/common/uloc.cpp
index ebfbb506508..a12c3f4cba1 100644
--- a/icu/icu4c/source/common/uloc.cpp
+++ b/icu/icu4c/source/common/uloc.cpp
@@ -1961,6 +1961,15 @@ uloc_getISO3Language(const char* localeID)
     return LANGUAGES_3[offset];
 }
 
+U_CAPI const char*  U_EXPORT2
+uloc_getISO3LanguageByLangCode(const char* langCode)
+{
+    int16_t offset = _findIndex(LANGUAGES, langCode);
+    if (offset < 0)
+        return "";
+    return LANGUAGES_3[offset];
+}
+
 U_CAPI const char*  U_EXPORT2
 uloc_getISO3Country(const char* localeID)
 {
@@ -1982,6 +1991,16 @@ uloc_getISO3Country(const char* localeID)
     return COUNTRIES_3[offset];
 }
 
+U_CAPI const char*  U_EXPORT2
+uloc_getISO3CountryByCountryCode(const char* countryCode)
+{
+    int16_t offset = _findIndex(COUNTRIES, countryCode);
+    if (offset < 0)
+        return "";
+
+    return COUNTRIES_3[offset];
+}
+
 U_CAPI uint32_t  U_EXPORT2
 uloc_getLCID(const char* localeID)
 {
diff --git a/icu/icu4c/source/common/unicode/uloc.h b/icu/icu4c/source/common/unicode/uloc.h
index 2c33c02bfd0..cf3466f6fbe 100644
--- a/icu/icu4c/source/common/unicode/uloc.h
+++ b/icu/icu4c/source/common/unicode/uloc.h
@@ -524,6 +524,15 @@ uloc_canonicalize(const char*    localeID,
 U_CAPI const char* U_EXPORT2
 uloc_getISO3Language(const char* localeID);
 
+/**
+ * Gets the 3 letter ISO language code for the specified 2 letter language code.
+ *
+ * @param langCode Iso639LanguageTwoLetterName
+ * @return language the ISO language code for langCode
+ * DOTNET CUSTOM API
+ */
+U_CAPI const char* U_EXPORT2
+uloc_getISO3LanguageByLangCode(const char* langCode);
 
 /**
  * Gets the ISO country code for the specified locale.
@@ -535,6 +544,16 @@ uloc_getISO3Language(const char* localeID);
 U_CAPI const char* U_EXPORT2
 uloc_getISO3Country(const char* localeID);
 
+/**
+ * Gets the 3 letter ISO country code for the specified 2 letter country code.
+ *
+ * @param countryCode Iso3166CountryName
+ * @return country the ISO country code for countryCode
+ * DOTNET CUSTOM API
+ */
+U_CAPI const char* U_EXPORT2
+uloc_getISO3CountryByCountryCode(const char* countryCode);
+
 /**
  * Gets the Win32 LCID value for the specified locale.
  * If the ICU locale is not recognized by Windows, 0 will be returned.
diff --git a/icu/icu4c/source/common/unicode/urename.h b/icu/icu4c/source/common/unicode/urename.h
index fe59fdd893d..d44ef92dce7 100644
--- a/icu/icu4c/source/common/unicode/urename.h
+++ b/icu/icu4c/source/common/unicode/urename.h
@@ -1082,7 +1082,9 @@
 #define uloc_getDisplayScript U_ICU_ENTRY_POINT_RENAME(uloc_getDisplayScript)
 #define uloc_getDisplayVariant U_ICU_ENTRY_POINT_RENAME(uloc_getDisplayVariant)
 #define uloc_getISO3Country U_ICU_ENTRY_POINT_RENAME(uloc_getISO3Country)
+#define uloc_getISO3CountryByCountryCode U_ICU_ENTRY_POINT_RENAME(uloc_getISO3CountryByCountryCode)
 #define uloc_getISO3Language U_ICU_ENTRY_POINT_RENAME(uloc_getISO3Language)
+#define uloc_getISO3LanguageByLangCode U_ICU_ENTRY_POINT_RENAME(uloc_getISO3LanguageByLangCode)
 #define uloc_getISOCountries U_ICU_ENTRY_POINT_RENAME(uloc_getISOCountries)
 #define uloc_getISOLanguages U_ICU_ENTRY_POINT_RENAME(uloc_getISOLanguages)
 #define uloc_getKeywordValue U_ICU_ENTRY_POINT_RENAME(uloc_getKeywordValue)