diff --git a/test/re/re.regex/re.regex.locale/imbue.pass.cpp b/test/re/re.regex/re.regex.locale/imbue.pass.cpp
index 58a1fdec..13572b5c 100644
--- a/test/re/re.regex/re.regex.locale/imbue.pass.cpp
+++ b/test/re/re.regex/re.regex.locale/imbue.pass.cpp
@@ -20,10 +20,10 @@
 int main()
 {
     std::regex r;
-    std::locale loc = r.imbue(std::locale("en_US"));
+    std::locale loc = r.imbue(std::locale("en_US.UTF-8"));
     assert(loc.name() == "C");
-    assert(r.getloc().name() == "en_US");
+    assert(r.getloc().name() == "en_US.UTF-8");
     loc = r.imbue(std::locale("C"));
-    assert(loc.name() == "en_US");
+    assert(loc.name() == "en_US.UTF-8");
     assert(r.getloc().name() == "C");
 }
diff --git a/test/re/re.traits/default.pass.cpp b/test/re/re.traits/default.pass.cpp
index e450c24f..f486a717 100644
--- a/test/re/re.traits/default.pass.cpp
+++ b/test/re/re.traits/default.pass.cpp
@@ -26,10 +26,10 @@ int main()
         assert(t2.getloc().name() == "C");
     }
     {
-        std::locale::global(std::locale("en_US"));
+        std::locale::global(std::locale("en_US.UTF-8"));
         std::regex_traits<char> t1;
-        assert(t1.getloc().name() == "en_US");
+        assert(t1.getloc().name() == "en_US.UTF-8");
         std::regex_traits<wchar_t> t2;
-        assert(t2.getloc().name() == "en_US");
+        assert(t2.getloc().name() == "en_US.UTF-8");
     }
 }
diff --git a/test/re/re.traits/getloc.pass.cpp b/test/re/re.traits/getloc.pass.cpp
index df6d6f18..0bda93d5 100644
--- a/test/re/re.traits/getloc.pass.cpp
+++ b/test/re/re.traits/getloc.pass.cpp
@@ -25,10 +25,10 @@ int main()
         assert(t2.getloc().name() == "C");
     }
     {
-        std::locale::global(std::locale("en_US"));
+        std::locale::global(std::locale("en_US.UTF-8"));
         std::regex_traits<char> t1;
-        assert(t1.getloc().name() == "en_US");
+        assert(t1.getloc().name() == "en_US.UTF-8");
         std::regex_traits<wchar_t> t2;
-        assert(t2.getloc().name() == "en_US");
+        assert(t2.getloc().name() == "en_US.UTF-8");
     }
 }
diff --git a/test/re/re.traits/imbue.pass.cpp b/test/re/re.traits/imbue.pass.cpp
index de1afa11..acdabda5 100644
--- a/test/re/re.traits/imbue.pass.cpp
+++ b/test/re/re.traits/imbue.pass.cpp
@@ -21,8 +21,8 @@ int main()
 {
     {
         std::regex_traits<char> t;
-        std::locale loc = t.imbue(std::locale("en_US"));
+        std::locale loc = t.imbue(std::locale("en_US.UTF-8"));
         assert(loc.name() == "C");
-        assert(t.getloc().name() == "en_US");
+        assert(t.getloc().name() == "en_US.UTF-8");
     }
 }
diff --git a/test/re/re.traits/translate_nocase.pass.cpp b/test/re/re.traits/translate_nocase.pass.cpp
index 1a3d91b1..2d02b65c 100644
--- a/test/re/re.traits/translate_nocase.pass.cpp
+++ b/test/re/re.traits/translate_nocase.pass.cpp
@@ -29,7 +29,7 @@ int main()
         assert(t.translate_nocase('1') == '1');
         assert(t.translate_nocase('\xDA') == '\xDA');
         assert(t.translate_nocase('\xFA') == '\xFA');
-        t.imbue(std::locale("en_US"));
+        t.imbue(std::locale("en_US.UTF-8"));
         assert(t.translate_nocase(' ') == ' ');
         assert(t.translate_nocase('A') == 'a');
         assert(t.translate_nocase('\x07') == '\x07');
@@ -49,7 +49,7 @@ int main()
         assert(t.translate_nocase(L'1') == L'1');
         assert(t.translate_nocase(L'\xDA') == L'\xDA');
         assert(t.translate_nocase(L'\xFA') == L'\xFA');
-        t.imbue(std::locale("en_US"));
+        t.imbue(std::locale("en_US.UTF-8"));
         assert(t.translate_nocase(L' ') == L' ');
         assert(t.translate_nocase(L'A') == L'a');
         assert(t.translate_nocase(L'\x07') == L'\x07');