diff --git a/src/dawn_wire/client/Buffer.cpp b/src/dawn_wire/client/Buffer.cpp
index 5fc7fbb20c..4515caf0ed 100644
--- a/src/dawn_wire/client/Buffer.cpp
+++ b/src/dawn_wire/client/Buffer.cpp
@@ -26,7 +26,7 @@ namespace dawn_wire { namespace client {
         bool mappable =
             (descriptor->usage & (WGPUBufferUsage_MapRead | WGPUBufferUsage_MapWrite)) != 0 ||
             descriptor->mappedAtCreation;
-        if (mappable && descriptor->size > std::numeric_limits<size_t>::max()) {
+        if (mappable && descriptor->size >= std::numeric_limits<size_t>::max()) {
             device_->InjectError(WGPUErrorType_OutOfMemory, "Buffer is too large for map usage");
             return device_->CreateErrorBuffer();
         }
diff --git a/src/tests/unittests/wire/WireBufferMappingTests.cpp b/src/tests/unittests/wire/WireBufferMappingTests.cpp
index 8b948aef79..1f0f31ba4b 100644
--- a/src/tests/unittests/wire/WireBufferMappingTests.cpp
+++ b/src/tests/unittests/wire/WireBufferMappingTests.cpp
@@ -630,3 +630,47 @@ TEST_F(WireBufferMappingTests, MappedAtCreationThenMapFailure) {
 
     FlushClient();
 }
+
+// Check that trying to create a buffer of size MAX_SIZE_T is an error handling in the client and
+// never gets to the server-side.
+TEST_F(WireBufferMappingTests, MaxSizeMappableBufferOOMDirectly) {
+    size_t kOOMSize = std::numeric_limits<size_t>::max();
+    WGPUBuffer apiBuffer = api.GetNewBuffer();
+
+    // Check for CreateBufferMapped.
+    {
+        WGPUBufferDescriptor descriptor = {};
+        descriptor.usage = WGPUBufferUsage_CopySrc;
+        descriptor.size = kOOMSize;
+        descriptor.mappedAtCreation = true;
+
+        wgpuDeviceCreateBuffer(device, &descriptor);
+        EXPECT_CALL(api, DeviceInjectError(apiDevice, WGPUErrorType_OutOfMemory, _));
+        EXPECT_CALL(api, DeviceCreateErrorBuffer(apiDevice)).WillOnce(Return(apiBuffer));
+        FlushClient();
+    }
+
+    // Check for MapRead usage.
+    {
+        WGPUBufferDescriptor descriptor = {};
+        descriptor.usage = WGPUBufferUsage_MapRead;
+        descriptor.size = kOOMSize;
+
+        wgpuDeviceCreateBuffer(device, &descriptor);
+        EXPECT_CALL(api, DeviceInjectError(apiDevice, WGPUErrorType_OutOfMemory, _));
+        EXPECT_CALL(api, DeviceCreateErrorBuffer(apiDevice)).WillOnce(Return(apiBuffer));
+        FlushClient();
+    }
+
+    // Check for MapWrite usage.
+    {
+        WGPUBufferDescriptor descriptor = {};
+        descriptor.usage = WGPUBufferUsage_MapWrite;
+        descriptor.size = kOOMSize;
+
+        wgpuDeviceCreateBuffer(device, &descriptor);
+        EXPECT_CALL(api, DeviceInjectError(apiDevice, WGPUErrorType_OutOfMemory, _));
+        EXPECT_CALL(api, DeviceCreateErrorBuffer(apiDevice)).WillOnce(Return(apiBuffer));
+        FlushClient();
+    }
+}