diff --git a/system/Router/RouteCollection.php b/system/Router/RouteCollection.php
index 2e3aa0a9c07e..76f3a9989b07 100644
--- a/system/Router/RouteCollection.php
+++ b/system/Router/RouteCollection.php
@@ -271,6 +271,11 @@ class RouteCollection implements RouteCollectionInterface
      */
     private ?string $httpHost = null;
 
+    /**
+     * Whether create() has already loaded the array helper.
+     */
+    private bool $arrayHelperLoaded = false;
+
     /**
      * Flag to limit or not the routes with {locale} placeholder to App::$supportedLocales
      */
@@ -1399,8 +1404,11 @@ protected function create(string $verb, string $from, $to, ?array $options = nul
 
         // Replace our regex pattern placeholders with the actual thing
         // so that the Router doesn't need to know about any of this.
-        foreach ($this->placeholders as $tag => $pattern) {
-            $routeKey = str_ireplace(':' . $tag, $pattern, $routeKey);
+        // Without a ':' no placeholder can match, so skip the loop.
+        if (str_contains($routeKey, ':')) {
+            foreach ($this->placeholders as $tag => $pattern) {
+                $routeKey = str_ireplace(':' . $tag, $pattern, $routeKey);
+            }
         }
 
         // If is redirect, No processing
@@ -1417,7 +1425,11 @@ protected function create(string $verb, string $from, $to, ?array $options = nul
 
         $name = $options['as'] ?? $routeKey;
 
-        helper('array');
+        // Not used here; kept so apps relying on the helper being loaded keep working.
+        if (! $this->arrayHelperLoaded) {
+            helper('array');
+            $this->arrayHelperLoaded = true;
+        }
 
         // Don't overwrite any existing 'froms' so that auto-discovered routes
         // do not overwrite any app/Config/Routes settings. The app
diff --git a/tests/system/Router/RouteCollectionTest.php b/tests/system/Router/RouteCollectionTest.php
index 71a4959d7d0f..0769b23c1b25 100644
--- a/tests/system/Router/RouteCollectionTest.php
+++ b/tests/system/Router/RouteCollectionTest.php
@@ -248,6 +248,50 @@ public function testAddReplacesCustomPlaceholders(): void
         $this->assertSame($expects, $routes);
     }
 
+    public function testAddWithoutPlaceholdersKeepsExactKey(): void
+    {
+        $routes = $this->getCollector();
+
+        $routes->add('users/profile-edit', 'controller');
+        $routes->add('products/([a-z]+)/(\d+)', 'controller');
+
+        $expects = [
+            'users/profile-edit'      => '\controller',
+            'products/([a-z]+)/(\d+)' => '\controller',
+        ];
+
+        $this->assertSame($expects, $routes->getRoutes());
+    }
+
+    public function testAddReplacesCustomNonCapturingPlaceholderMixedWithDefaults(): void
+    {
+        $routes = $this->getCollector();
+        $routes->addPlaceholder('slug', '(?:[a-z]+-)*[a-z]+');
+
+        $routes->add('blog/(:num)/(:slug)/(:segment)', 'controller');
+
+        $expects = [
+            'blog/([0-9]+)/((?:[a-z]+-)*[a-z]+)/([^/]+)' => '\controller',
+        ];
+
+        $this->assertSame($expects, $routes->getRoutes());
+    }
+
+    public function testAddReplacesPlaceholdersCaseInsensitivelyWithoutParentheses(): void
+    {
+        $routes = $this->getCollector();
+
+        $routes->add('users/(:NUM)', 'controller');
+        $routes->add('posts/:segment', 'controller');
+
+        $expects = [
+            'users/([0-9]+)' => '\controller',
+            'posts/[^/]+'    => '\controller',
+        ];
+
+        $this->assertSame($expects, $routes->getRoutes());
+    }
+
     public function testAddRecognizesCustomNamespaces(): void
     {
         $routes = $this->getCollector();
diff --git a/user_guide_src/source/changelogs/v4.8.0.rst b/user_guide_src/source/changelogs/v4.8.0.rst
index e3e116d1f996..ddfbee6915bb 100644
--- a/user_guide_src/source/changelogs/v4.8.0.rst
+++ b/user_guide_src/source/changelogs/v4.8.0.rst
@@ -455,6 +455,7 @@ Changes
 *******
 
 - **Config:** Added the ``md`` key for ``Config\Mimes::$mimes`` for Markdown files.
+- **Router:** Reduced route registration overhead in ``RouteCollection::create()`` by skipping placeholder replacement for route keys without ``:`` and calling ``helper('array')`` only once per collection.
 
 ************
 Deprecations