diff --git a/system/Router/Router.php b/system/Router/Router.php
index ea5eb79b8d70..c5985f95af30 100644
--- a/system/Router/Router.php
+++ b/system/Router/Router.php
@@ -403,9 +403,6 @@ protected function checkRoutes(string $uri): bool
 
         // Loop through the route array looking for wildcards
         foreach ($routes as $routeKey => $handler) {
-            // Reset localeSegment
-            $localeSegment = null;
-
             $routeKey = $routeKey === '/'
                 ? $routeKey
                 : ltrim($routeKey, '/ ');
@@ -414,12 +411,7 @@ protected function checkRoutes(string $uri): bool
 
             // Are we dealing with a locale?
             if (strpos($routeKey, '{locale}') !== false) {
-                $localeSegment = array_search('{locale}', preg_split('/[\/]*((^[a-zA-Z0-9])|\(([^()]*)\))*[\/]+/m', $routeKey), true);
-
-                // Replace it with a regex so it
-                // will actually match.
-                $routeKey = str_replace('/', '\/', $routeKey);
-                $routeKey = str_replace('{locale}', '[^\/]+', $routeKey);
+                $routeKey = str_replace('{locale}', '[^/]+', $routeKey);
             }
 
             // Does the RegEx match?
@@ -440,10 +432,15 @@ protected function checkRoutes(string $uri): bool
                 }
                 // Store our locale so CodeIgniter object can
                 // assign it to the Request.
-                if (isset($localeSegment)) {
-                    // The following may be inefficient, but doesn't upset NetBeans :-/
-                    $temp                 = (explode('/', $uri));
-                    $this->detectedLocale = $temp[$localeSegment];
+                if (strpos($matchedKey, '{locale}') !== false) {
+                    preg_match(
+                        '#^' . str_replace('{locale}', '(?<locale>[^/]+)', $matchedKey) . '$#u',
+                        $uri,
+                        $matched
+                    );
+
+                    $this->detectedLocale = $matched['locale'];
+                    unset($matched);
                 }
 
                 // Are we using Closures? If so, then we need
diff --git a/tests/system/Router/RouterTest.php b/tests/system/Router/RouterTest.php
index d2e48bff992d..db9cd9c5e7e9 100644
--- a/tests/system/Router/RouterTest.php
+++ b/tests/system/Router/RouterTest.php
@@ -47,6 +47,7 @@ protected function setUp(): void
             'books/(:num)/(:alpha)/(:num)'                    => 'Blog::show/$3/$1',
             'closure/(:num)/(:alpha)'                         => static fn ($num, $str) => $num . '-' . $str,
             '{locale}/pages'                                  => 'App\Pages::list_all',
+            'test/(:any)/lang/{locale}'                       => 'App\Pages::list_all',
             'admin/admins'                                    => 'App\Admin\Admins::list_all',
             'admin/admins/edit/(:any)'                        => 'App/Admin/Admins::edit_show/$1',
             '/some/slash'                                     => 'App\Slash::index',
@@ -402,6 +403,11 @@ public function testDetectsLocales()
 
         $this->assertTrue($router->hasLocale());
         $this->assertSame('fr', $router->getLocale());
+
+        $router->handle('test/123/lang/bg');
+
+        $this->assertTrue($router->hasLocale());
+        $this->assertSame('bg', $router->getLocale());
     }
 
     public function testRouteResource()