diff --git a/Source/Core/Core/Movie.cpp b/Source/Core/Core/Movie.cpp
index c62130e18c9..c5d0338917d 100644
--- a/Source/Core/Core/Movie.cpp
+++ b/Source/Core/Core/Movie.cpp
@@ -159,8 +159,15 @@ std::string MovieManager::GetRTCDisplay() const
   const time_t current_time = CEXIIPL::GetEmulatedTime(m_system, CEXIIPL::UNIX_EPOCH);
   const tm gm_time = fmt::gmtime(current_time);
 
-  // Use current locale for formatting time, as fmt is locale-agnostic by default.
+#if FMT_VERSION < 120000  // fmt < 12 still supports locale overload
   return fmt::format(std::locale{""}, "Date/Time: {:%c}", gm_time);
+#else
+  // fmt >= 12: no locale overload, fall back to standard library
+  std::ostringstream oss;
+  oss.imbue(std::locale(""));
+  oss << "Date/Time: " << std::put_time(&gm_time, "%c");
+  return oss.str();
+#endif
 }
 
 // NOTE: GPU Thread
diff --git a/Source/Core/Core/State.cpp b/Source/Core/Core/State.cpp
index ffd811bd6c7..0bcbac1fc9a 100644
--- a/Source/Core/Core/State.cpp
+++ b/Source/Core/Core/State.cpp
@@ -285,8 +285,14 @@ static std::string SystemTimeAsDoubleToString(double time)
   if (!local_time)
     return "";
 
-  // fmt is locale agnostic by default, so explicitly use current locale.
+#if FMT_VERSION < 120000  // fmt < 12 still supports locale overload
   return fmt::format(std::locale{""}, "{:%x %X}", *local_time);
+#else
+  std::ostringstream oss;
+  oss.imbue(std::locale(""));
+  oss << std::put_time(&*local_time, "%x %X");
+  return oss.str();
+#endif
 }
 
 static std::string MakeStateFilename(int number);