diff --git a/src/Symfony/Component/Routing/Requirement/EnumRequirement.php b/src/Symfony/Component/Routing/Requirement/EnumRequirement.php
index ba5078cda3f8a..2a369845c4eb4 100644
--- a/src/Symfony/Component/Routing/Requirement/EnumRequirement.php
+++ b/src/Symfony/Component/Routing/Requirement/EnumRequirement.php
@@ -15,36 +15,42 @@
 
 final class EnumRequirement implements \Stringable
 {
-    /**
-     * @var string[]
-     */
-    private readonly array $values;
+    private string $requirement;
 
     /**
      * @template T of \BackedEnum
-     * @param class-string<T> $enum
-     * @param T ...$cases
+     *
+     * @param class-string<T>|list<T> $cases
      */
-    public function __construct(string $enum, \BackedEnum ...$cases)
+    public function __construct(string|array $cases = [])
     {
-        if (!\is_subclass_of($enum, \BackedEnum::class, true)) {
-            throw new InvalidArgumentException(sprintf('"%s" is not a \BackedEnum class.', $enum));
-        }
+        if (\is_string($cases)) {
+            if (!is_subclass_of($cases, \BackedEnum::class, true)) {
+                throw new InvalidArgumentException(sprintf('"%s" is not a "BackedEnum" class.', $cases));
+            }
+
+            $cases = $cases::cases();
+        } else {
+            $class = null;
+
+            foreach ($cases as $case) {
+                if (!$case instanceof \BackedEnum) {
+                    throw new InvalidArgumentException(sprintf('Case must be a "BackedEnum" instance, "%s" given.', get_debug_type($case)));
+                }
+
+                $class ??= \get_class($case);
 
-        foreach ($cases as $case) {
-            if (!$case instanceof $enum) {
-                throw new InvalidArgumentException(sprintf('"%s::%s" is not a case of "%s".', \get_class($case), $case->name, $enum));
+                if (!$case instanceof $class) {
+                    throw new InvalidArgumentException(sprintf('"%s::%s" is not a case of "%s".', get_debug_type($case), $case->name, $class));
+                }
             }
         }
 
-        $this->values = array_map(
-            static fn (\BackedEnum $e): string => $e->value,
-            $cases ?: $enum::cases(),
-        );
+        $this->requirement = implode('|', array_map(static fn ($e) => preg_quote($e->value), $cases));
     }
 
     public function __toString(): string
     {
-        return implode('|', array_map(preg_quote(...), $this->values));
+        return $this->requirement;
     }
 }
diff --git a/src/Symfony/Component/Routing/Tests/Requirement/EnumRequirementTest.php b/src/Symfony/Component/Routing/Tests/Requirement/EnumRequirementTest.php
index 18484c03d142a..75613f4985575 100644
--- a/src/Symfony/Component/Routing/Tests/Requirement/EnumRequirementTest.php
+++ b/src/Symfony/Component/Routing/Tests/Requirement/EnumRequirementTest.php
@@ -25,25 +25,33 @@ class EnumRequirementTest extends TestCase
     public function testNotABackedEnum()
     {
         $this->expectException(InvalidArgumentException::class);
-        $this->expectExceptionMessage('"Symfony\Component\Routing\Tests\Fixtures\Enum\TestUnitEnum" is not a \BackedEnum class.');
+        $this->expectExceptionMessage('"Symfony\Component\Routing\Tests\Fixtures\Enum\TestUnitEnum" is not a "BackedEnum" class.');
 
         new EnumRequirement(TestUnitEnum::class);
     }
 
+    public function testCaseNotABackedEnum()
+    {
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('Case must be a "BackedEnum" instance, "string" given.');
+
+        new EnumRequirement(['wrong']);
+    }
+
     public function testCaseFromAnotherEnum()
     {
         $this->expectException(InvalidArgumentException::class);
         $this->expectExceptionMessage('"Symfony\Component\Routing\Tests\Fixtures\Enum\TestStringBackedEnum2::Spades" is not a case of "Symfony\Component\Routing\Tests\Fixtures\Enum\TestStringBackedEnum".');
 
-        new EnumRequirement(TestStringBackedEnum::class, TestStringBackedEnum::Diamonds, TestStringBackedEnum2::Spades);
+        new EnumRequirement([TestStringBackedEnum::Diamonds, TestStringBackedEnum2::Spades]);
     }
 
     /**
      * @dataProvider provideToString
      */
-    public function testToString(string $expected, string $enum, \BackedEnum ...$cases)
+    public function testToString(string $expected, string|array $cases = [])
     {
-        $this->assertSame($expected, (string) new EnumRequirement($enum, ...$cases));
+        $this->assertSame($expected, (string) new EnumRequirement($cases));
     }
 
     public function provideToString()
@@ -51,7 +59,8 @@ public function provideToString()
         return [
             ['hearts|diamonds|clubs|spades', TestStringBackedEnum::class],
             ['10|20|30|40', TestIntBackedEnum::class],
-            ['diamonds|spades', TestStringBackedEnum::class, TestStringBackedEnum::Diamonds, TestStringBackedEnum::Spades],
+            ['diamonds|spades', [TestStringBackedEnum::Diamonds, TestStringBackedEnum::Spades]],
+            ['diamonds', [TestStringBackedEnum::Diamonds]],
             ['hearts|diamonds|clubs|spa\|des', TestStringBackedEnum2::class],
         ];
     }