diff --git a/.changeset/deploy-no-build-missing-web-pixel-bundle.md b/.changeset/deploy-no-build-missing-web-pixel-bundle.md
new file mode 100644
index 00000000000..65d1741540c
--- /dev/null
+++ b/.changeset/deploy-no-build-missing-web-pixel-bundle.md
@@ -0,0 +1,5 @@
+---
+'@shopify/app': patch
+---
+
+Show a clear error instead of ENOENT when `app deploy --no-build` finds no built web pixel bundle.
diff --git a/packages/app/src/cli/services/build/errors.ts b/packages/app/src/cli/services/build/errors.ts
new file mode 100644
index 00000000000..ab80157597d
--- /dev/null
+++ b/packages/app/src/cli/services/build/errors.ts
@@ -0,0 +1,14 @@
+import {AbortError} from '@shopify/cli-kit/node/error'
+
+/**
+ * The build output doesn't exist, usually after `deploy --no-build`.
+ * A developer condition, not a CLI defect, so it stays out of crash reporting.
+ */
+export class MissingBuildOutputError extends AbortError {
+  constructor(outputPath: string) {
+    super(
+      `Couldn't find the build output at ${outputPath}`,
+      'If you passed --no-build, build the app first. Otherwise check that building the extension produces files at that path.',
+    )
+  }
+}
diff --git a/packages/app/src/cli/services/build/extension.test.ts b/packages/app/src/cli/services/build/extension.test.ts
index a1da883761d..66b86170494 100644
--- a/packages/app/src/cli/services/build/extension.test.ts
+++ b/packages/app/src/cli/services/build/extension.test.ts
@@ -1,5 +1,5 @@
-import {buildFunctionExtension} from './extension.js'
-import {testFunctionExtension} from '../../models/app/app.test-data.js'
+import {buildFunctionExtension, buildUIExtension} from './extension.js'
+import {testFunctionExtension, testUIExtension} from '../../models/app/app.test-data.js'
 import {buildGraphqlTypes, buildJSFunction, runWasmOpt, runTrampoline} from '../function/build.js'
 import {validateSchemaApiVersion} from '../function/schema-version.js'
 import {FunctionConfigType} from '../../models/extensions/specifications/function.js'
@@ -528,3 +528,27 @@ describe('buildFunctionExtension', () => {
     })
   })
 })
+
+describe('buildUIExtension', () => {
+  test('aborts with a clear error when skipBuild is set and the web pixel bundle is missing', async () => {
+    await fs.inTemporaryDirectory(async (tmpDir) => {
+      // Given
+      const extension = await testUIExtension({type: 'web_pixel_extension', directory: tmpDir})
+      const options = {
+        stdout: {write: vi.fn()} as unknown as Writable,
+        stderr: {write: vi.fn()} as unknown as Writable,
+        app: {} as any,
+        environment: 'production' as const,
+        skipBuild: true,
+      }
+      const localOutputPath = joinPath(tmpDir, extension.outputRelativePath)
+
+      // When
+      const result = buildUIExtension(extension, options)
+
+      // Then
+      await expect(result).rejects.toThrowError(AbortError)
+      await expect(result).rejects.toThrow(`Couldn't find the build output at ${localOutputPath}`)
+    })
+  })
+})
diff --git a/packages/app/src/cli/services/build/extension.ts b/packages/app/src/cli/services/build/extension.ts
index 1fd1c06ea20..885118cafc5 100644
--- a/packages/app/src/cli/services/build/extension.ts
+++ b/packages/app/src/cli/services/build/extension.ts
@@ -1,4 +1,5 @@
 import {formatBundleSize} from './bundle-size.js'
+import {MissingBuildOutputError} from './errors.js'
 import {AppInterface} from '../../models/app/app.js'
 import {bundleExtension} from '../extensions/bundle.js'
 import {buildGraphqlTypes, buildJSFunction, runTrampoline, runWasmOpt} from '../function/build.js'
@@ -12,7 +13,7 @@ import {AbortError, AbortSilentError} from '@shopify/cli-kit/node/error'
 import lockfile from 'proper-lockfile'
 import {dirname, joinPath} from '@shopify/cli-kit/node/path'
 import {outputDebug} from '@shopify/cli-kit/node/output'
-import {readFile, touchFile, writeFile, fileExistsSync} from '@shopify/cli-kit/node/fs'
+import {fileExists, readFile, touchFile, writeFile, fileExistsSync} from '@shopify/cli-kit/node/fs'
 import {Writable} from 'stream'
 // eslint-disable-next-line no-restricted-imports
 import {resolve} from 'node:path'
@@ -135,6 +136,11 @@ export async function buildUIExtension(extension: ExtensionInstance, options: Ex
     }
   }
 
+  // Validations such as the web pixel size check read the output file.
+  if (options.skipBuild && !(await fileExists(localOutputPath))) {
+    throw new MissingBuildOutputError(localOutputPath)
+  }
+
   await extension.buildValidation({outputPath: localOutputPath})
 
   const duration = Math.round(performance.now() - startTime)
diff --git a/packages/app/src/cli/services/build/steps/bundle-ui-step.ts b/packages/app/src/cli/services/build/steps/bundle-ui-step.ts
index 738964da6e4..f9acb3b46ff 100644
--- a/packages/app/src/cli/services/build/steps/bundle-ui-step.ts
+++ b/packages/app/src/cli/services/build/steps/bundle-ui-step.ts
@@ -1,9 +1,9 @@
 import {createOrUpdateManifestFile} from './include-assets/generate-manifest.js'
 import {buildUIExtension} from '../extension.js'
+import {MissingBuildOutputError} from '../errors.js'
 import {BuildManifest} from '../../../models/extensions/specifications/ui_extension.js'
 import {copyFile, fileExists, glob, mkdir} from '@shopify/cli-kit/node/fs'
 import {dirname, joinPath, relativePath, resolvePath} from '@shopify/cli-kit/node/path'
-import {AbortError} from '@shopify/cli-kit/node/error'
 import type {BundleUIStep, BuildContext} from '../client-steps.js'
 
 interface ExtensionPointWithBuildManifest {
@@ -31,13 +31,9 @@ export async function executeBundleUIStep(step: BundleUIStep, context: BuildCont
   // If the final output path is the same as the local one: don't copy the results and don't generate manifests.
   if (resolvePath(localOutputDir) === resolvePath(bundleOutputDir)) return
 
-  // Nothing was built, usually `deploy --no-build`. A developer condition, not a
-  // CLI defect, so keep it out of crash reporting.
+  // Nothing was built, usually `deploy --no-build`.
   if (!(await fileExists(localOutputDir))) {
-    throw new AbortError(
-      `Couldn't find the build output at ${localOutputDir}`,
-      'If you passed --no-build, build the app first. Otherwise check that building the extension produces files at that path.',
-    )
+    throw new MissingBuildOutputError(localOutputDir)
   }
 
   // Source maps stay in the extension's local output directory and are excluded