diff --git a/onnxruntime/core/providers/webgpu/tensor/flatten.cc b/onnxruntime/core/providers/webgpu/tensor/flatten.cc
index 81d28bd3c0..11ded865b6 100644
--- a/onnxruntime/core/providers/webgpu/tensor/flatten.cc
+++ b/onnxruntime/core/providers/webgpu/tensor/flatten.cc
@@ -13,7 +13,10 @@ ONNX_OPERATOR_VERSIONED_KERNEL_EX(
     kOnnxDomain,
     1, 8,
     kWebGpuExecutionProvider,
-    (*KernelDefBuilder::Create()).TypeConstraint("T", WebGpuSupportedFloatTypes()).InputMemoryType(OrtMemTypeCPU, 1),
+    (*KernelDefBuilder::Create())
+        .Alias(0, 0)
+        .TypeConstraint("T", WebGpuSupportedNumberTypes())
+        .InputMemoryType(OrtMemTypeCPU, 1),
     Flatten);
 
 ONNX_OPERATOR_VERSIONED_KERNEL_EX(
@@ -21,7 +24,10 @@ ONNX_OPERATOR_VERSIONED_KERNEL_EX(
     kOnnxDomain,
     9, 10,
     kWebGpuExecutionProvider,
-    (*KernelDefBuilder::Create()).TypeConstraint("T", WebGpuSupportedFloatTypes()).InputMemoryType(OrtMemTypeCPU, 1),
+    (*KernelDefBuilder::Create())
+        .Alias(0, 0)
+        .TypeConstraint("T", WebGpuSupportedNumberTypes())
+        .InputMemoryType(OrtMemTypeCPU, 1),
     Flatten);
 
 ONNX_OPERATOR_VERSIONED_KERNEL_EX(
@@ -29,7 +35,10 @@ ONNX_OPERATOR_VERSIONED_KERNEL_EX(
     kOnnxDomain,
     11, 12,
     kWebGpuExecutionProvider,
-    (*KernelDefBuilder::Create()).TypeConstraint("T", WebGpuSupportedFloatTypes()).InputMemoryType(OrtMemTypeCPU, 1),
+    (*KernelDefBuilder::Create())
+        .Alias(0, 0)
+        .TypeConstraint("T", WebGpuSupportedNumberTypes())
+        .InputMemoryType(OrtMemTypeCPU, 1),
     Flatten);
 
 ONNX_OPERATOR_VERSIONED_KERNEL_EX(
@@ -37,7 +46,10 @@ ONNX_OPERATOR_VERSIONED_KERNEL_EX(
     kOnnxDomain,
     13, 20,
     kWebGpuExecutionProvider,
-    (*KernelDefBuilder::Create()).TypeConstraint("T", WebGpuSupportedFloatTypes()).InputMemoryType(OrtMemTypeCPU, 1),
+    (*KernelDefBuilder::Create())
+        .Alias(0, 0)
+        .TypeConstraint("T", WebGpuSupportedNumberTypes())
+        .InputMemoryType(OrtMemTypeCPU, 1),
     Flatten);
 
 ONNX_OPERATOR_KERNEL_EX(
@@ -45,8 +57,11 @@ ONNX_OPERATOR_KERNEL_EX(
     kOnnxDomain,
     21,
     kWebGpuExecutionProvider,
-    (*KernelDefBuilder::Create()).TypeConstraint("T", WebGpuSupportedFloatTypes()).InputMemoryType(OrtMemTypeCPU, 1),
+    (*KernelDefBuilder::Create())
+        .Alias(0, 0)
+        .TypeConstraint("T", WebGpuSupportedNumberTypes())
+        .InputMemoryType(OrtMemTypeCPU, 1),
     Flatten);
 
 }  // namespace webgpu
-}  // namespace onnxruntime
\ No newline at end of file
+}  // namespace onnxruntime