diff --git a/src/inspector_io.cc b/src/inspector_io.cc
index 538cbab3c9fe84..539cdb55019516 100644
--- a/src/inspector_io.cc
+++ b/src/inspector_io.cc
@@ -74,11 +74,11 @@ std::string StringViewToUtf8(const StringView& view) {
 
   size_t result_length = view.length() * sizeof(*source);
   std::string result(result_length, '\0');
-  UnicodeString utf16(unicodeSource, view.length());
+  icu::UnicodeString utf16(unicodeSource, view.length());
   // ICU components for std::string compatibility are not enabled in build...
   bool done = false;
   while (!done) {
-    CheckedArrayByteSink sink(&result[0], result_length);
+    icu::CheckedArrayByteSink sink(&result[0], result_length);
     utf16.toUTF8(sink);
     result_length = sink.NumberOfBytesAppended();
     result.resize(result_length);
@@ -111,8 +111,9 @@ void ReleasePairOnAsyncClose(uv_handle_t* async) {
 }  // namespace
 
 std::unique_ptr<StringBuffer> Utf8ToStringView(const std::string& message) {
-  UnicodeString utf16 =
-      UnicodeString::fromUTF8(StringPiece(message.data(), message.length()));
+  icu::UnicodeString utf16 =
+    icu::UnicodeString::fromUTF8(icu::StringPiece(message.data(),
+      message.length()));
   StringView view(reinterpret_cast<const uint16_t*>(utf16.getBuffer()),
                   utf16.length());
   return StringBuffer::create(view);
diff --git a/src/node_i18n.cc b/src/node_i18n.cc
index cc02092dd8630a..1fbc3dcb6b8556 100644
--- a/src/node_i18n.cc
+++ b/src/node_i18n.cc
@@ -523,7 +523,7 @@ const char* GetVersion(const char* type,
   } else if (!strcmp(type, TYPE_UNICODE)) {
     return U_UNICODE_VERSION;
   } else if (!strcmp(type, TYPE_TZ)) {
-    return TimeZone::getTZDataVersion(*status);
+    return icu::TimeZone::getTZDataVersion(*status);
   } else if (!strcmp(type, TYPE_CLDR)) {
     UVersionInfo versionArray;
     ulocdata_getCLDRVersion(versionArray, status);
diff --git a/tools/icu/iculslocs.cc b/tools/icu/iculslocs.cc
index ca312b783565c4..3ceb8d2a4d81d0 100644
--- a/tools/icu/iculslocs.cc
+++ b/tools/icu/iculslocs.cc
@@ -64,7 +64,7 @@ int VERBOSE = 0;
 #define RES_INDEX "res_index"
 #define INSTALLEDLOCALES "InstalledLocales"
 
-CharString packageName;
+icu::CharString packageName;
 const char* locale = RES_INDEX;  // locale referring to our index
 
 void usage() {
@@ -147,7 +147,7 @@ int localeExists(const char* loc, UBool* exists) {
   if (VERBOSE > 1) {
     printf("Trying to open %s:%s\n", packageName.data(), loc);
   }
-  LocalUResourceBundlePointer aResource(
+  icu::LocalUResourceBundlePointer aResource(
       ures_openDirect(packageName.data(), loc, &status));
   *exists = FALSE;
   if (U_SUCCESS(status)) {
@@ -189,11 +189,11 @@ void printIndent(FILE* bf, int indent) {
  * @return 0 for OK, 1 for err
  */
 int dumpAllButInstalledLocales(int lev,
-                               LocalUResourceBundlePointer* bund,
+                               icu::LocalUResourceBundlePointer* bund,
                                FILE* bf,
                                UErrorCode* status) {
   ures_resetIterator(bund->getAlias());
-  LocalUResourceBundlePointer t;
+  icu::LocalUResourceBundlePointer t;
   while (U_SUCCESS(*status) && ures_hasNext(bund->getAlias())) {
     t.adoptInstead(ures_getNextResource(bund->getAlias(), t.orphan(), status));
     ASSERT_SUCCESS(status, "while processing table");
@@ -254,10 +254,10 @@ int list(const char* toBundle) {
     printf("\"locale\": %s\n", locale);
   }
 
-  LocalUResourceBundlePointer bund(
+  icu::LocalUResourceBundlePointer bund(
       ures_openDirect(packageName.data(), locale, &status));
   ASSERT_SUCCESS(&status, "while opening the bundle");
-  LocalUResourceBundlePointer installedLocales(
+  icu::LocalUResourceBundlePointer installedLocales(
       // NOLINTNEXTLINE (readability/null_usage)
       ures_getByKey(bund.getAlias(), INSTALLEDLOCALES, NULL, &status));
   ASSERT_SUCCESS(&status, "while fetching installed locales");
@@ -295,7 +295,7 @@ int list(const char* toBundle) {
   }
 
   // OK, now list them.
-  LocalUResourceBundlePointer subkey;
+  icu::LocalUResourceBundlePointer subkey;
 
   int validCount = 0;
   for (int32_t i = 0; i < count; i++) {