diff --git a/system/Filters/Filters.php b/system/Filters/Filters.php
index 994c6f37c7e2..d93de522f6fa 100644
--- a/system/Filters/Filters.php
+++ b/system/Filters/Filters.php
@@ -154,7 +154,18 @@ private function discoverFilters(): void
 
         $files = $locator->search('Config/Filters.php');
 
+        // Our main Filter configs are never included again, see below. Skip them
+        // by path, as reading and tokenizing them to find that out is wasted work.
+        $mainFiles = [
+            APPPATH . 'Config' . DIRECTORY_SEPARATOR . 'Filters.php',
+            SYSTEMPATH . 'Config' . DIRECTORY_SEPARATOR . 'Filters.php',
+        ];
+
         foreach ($files as $file) {
+            if (in_array($file, $mainFiles, true)) {
+                continue;
+            }
+
             // The $file may not be a class file.
             $className = $locator->getClassname($file);
 
diff --git a/tests/system/Filters/FiltersTest.php b/tests/system/Filters/FiltersTest.php
index d696498efaa2..cb91393358ed 100644
--- a/tests/system/Filters/FiltersTest.php
+++ b/tests/system/Filters/FiltersTest.php
@@ -13,6 +13,7 @@
 
 namespace CodeIgniter\Filters;
 
+use CodeIgniter\Autoloader\FileLocator;
 use CodeIgniter\Config\Services;
 use CodeIgniter\Filters\Exceptions\FilterException;
 use CodeIgniter\Filters\fixtures\GoogleCurious;
@@ -488,6 +489,52 @@ public function testAllCustomFiltersAreDiscoveredInConstructor(): void
         $this->assertContains('test-customfilter', array_keys($configFilters->aliases));
     }
 
+    public function testDiscoveryDoesNotTokenizeTheDefaultFiltersConfigs(): void
+    {
+        service('superglobals')->setServer('REQUEST_METHOD', 'GET');
+
+        $locator = new class (service('autoloader')) extends FileLocator {
+            /**
+             * @var list<string>
+             */
+            public array $tokenized = [];
+
+            public function getClassname(string $file): string
+            {
+                $this->tokenized[] = $file;
+
+                return parent::getClassname($file);
+            }
+        };
+        Services::injectMock('locator', $locator);
+
+        $appConfig    = APPPATH . 'Config' . DIRECTORY_SEPARATOR . 'Filters.php';
+        $systemConfig = SYSTEMPATH . 'Config' . DIRECTORY_SEPARATOR . 'Filters.php';
+        $testConfig   = realpath(TESTPATH . '_support/Config/Filters.php');
+
+        // Discovery does find them all, so the checks below are not vacuous.
+        $found = $locator->search('Config/Filters.php');
+        $this->assertContains($appConfig, $found);
+        $this->assertContains($systemConfig, $found);
+        $this->assertContains($testConfig, $found);
+
+        $config = [
+            'aliases' => [],
+            'globals' => [],
+        ];
+        $filtersConfig = $this->createConfigFromArray(FiltersConfig::class, $config);
+        $filters       = $this->createFilters($filtersConfig);
+
+        $this->assertNotContains($appConfig, $locator->tokenized);
+        $this->assertNotContains($systemConfig, $locator->tokenized);
+
+        // Any other file is still checked and included.
+        $this->assertContains($testConfig, $locator->tokenized);
+
+        $configFilters = $this->getPrivateProperty($filters, 'config');
+        $this->assertContains('test-customfilter', array_keys($configFilters->aliases));
+    }
+
     public function testRunThrowsWithInvalidClassType(): void
     {
         service('superglobals')->setServer('REQUEST_METHOD', 'GET');