diff --git a/packages/compiler-vapor/__tests__/transforms/__snapshots__/vOnce.spec.ts.snap b/packages/compiler-vapor/__tests__/transforms/__snapshots__/vOnce.spec.ts.snap
index b255f5d0b..4b8e89d6d 100644
--- a/packages/compiler-vapor/__tests__/transforms/__snapshots__/vOnce.spec.ts.snap
+++ b/packages/compiler-vapor/__tests__/transforms/__snapshots__/vOnce.spec.ts.snap
@@ -1,6 +1,6 @@
 // Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
 
-exports[`v-once > as root node 1`] = `
+exports[`compiler: v-once > as root node 1`] = `
 "import { template as _template, children as _children, setAttr as _setAttr } from 'vue/vapor';
 
 export function render(_ctx) {
@@ -12,7 +12,7 @@ export function render(_ctx) {
 }"
 `;
 
-exports[`v-once > basic 1`] = `
+exports[`compiler: v-once > basic 1`] = `
 "import { template as _template, children as _children, createTextNode as _createTextNode, setText as _setText, setAttr as _setAttr, prepend as _prepend } from 'vue/vapor';
 
 export function render(_ctx) {
@@ -26,3 +26,25 @@ export function render(_ctx) {
   return n0
 }"
 `;
+
+exports[`compiler: v-once > inside v-once 1`] = `
+"import { template as _template } from 'vue/vapor';
+
+export function render(_ctx) {
+  const t0 = _template("<div><div></div></div>")
+  const n0 = t0()
+  return n0
+}"
+`;
+
+exports[`compiler: v-once > on nested plain element 1`] = `
+"import { template as _template, children as _children, setAttr as _setAttr } from 'vue/vapor';
+
+export function render(_ctx) {
+  const t0 = _template("<div><div></div></div>")
+  const n0 = t0()
+  const { 0: [, { 0: [n1],}],} = _children(n0)
+  _setAttr(n1, "id", undefined, _ctx.foo)
+  return n0
+}"
+`;
diff --git a/packages/compiler-vapor/__tests__/transforms/vOnce.spec.ts b/packages/compiler-vapor/__tests__/transforms/vOnce.spec.ts
index 8c87f3b2a..bdf493c0d 100644
--- a/packages/compiler-vapor/__tests__/transforms/vOnce.spec.ts
+++ b/packages/compiler-vapor/__tests__/transforms/vOnce.spec.ts
@@ -1,18 +1,36 @@
-import { type RootNode, BindingTypes } from '@vue/compiler-dom'
-import { type CompilerOptions, compile as _compile } from '../../src'
+import { BindingTypes, NodeTypes, parse } from '@vue/compiler-dom'
+import {
+  type CompilerOptions,
+  compile as _compile,
+  transform,
+  generate as generate,
+  IRNodeTypes,
+  RootIRNode,
+} from '../../src'
+import { getBaseTransformPreset } from '../../src/compile'
 
-function compile(template: string | RootNode, options: CompilerOptions = {}) {
-  let { code } = _compile(template, {
-    ...options,
-    mode: 'module',
+function compileWithOnce(
+  template: string,
+  options: CompilerOptions = {},
+): {
+  ir: RootIRNode
+  code: string
+} {
+  const ast = parse(template, { prefixIdentifiers: true, ...options })
+  const [nodeTransforms, directiveTransforms] = getBaseTransformPreset(true)
+  const ir = transform(ast, {
+    nodeTransforms,
+    directiveTransforms,
     prefixIdentifiers: true,
+    ...options,
   })
-  return code
+  const { code } = generate(ir, { prefixIdentifiers: true, ...options })
+  return { ir, code }
 }
 
-describe('v-once', () => {
+describe('compiler: v-once', () => {
   test('basic', () => {
-    const code = compile(
+    const { ir, code } = compileWithOnce(
       `<div v-once>
         {{ msg }}
         <span :class="clz" />
@@ -24,12 +42,118 @@ describe('v-once', () => {
         },
       },
     )
-    expect(code).matchSnapshot()
+    expect(ir.helpers.size).toBe(0)
+    expect(ir.effect).toEqual([])
+
+    expect(ir.operation).toMatchObject([
+      {
+        id: 1,
+        type: IRNodeTypes.CREATE_TEXT_NODE,
+        value: {
+          type: NodeTypes.SIMPLE_EXPRESSION,
+          content: 'msg',
+          isStatic: false,
+        },
+      },
+      {
+        element: 1,
+        type: IRNodeTypes.SET_TEXT,
+        value: {
+          type: NodeTypes.SIMPLE_EXPRESSION,
+          content: 'msg',
+          isStatic: false,
+        },
+      },
+      {
+        element: 2,
+        key: {
+          type: NodeTypes.SIMPLE_EXPRESSION,
+          content: 'class',
+          isStatic: true,
+        },
+        type: IRNodeTypes.SET_PROP,
+        value: {
+          type: NodeTypes.SIMPLE_EXPRESSION,
+          content: 'clz',
+          isStatic: false,
+        },
+      },
+      {
+        type: IRNodeTypes.PREPEND_NODE,
+        elements: [1],
+        parent: 3,
+      },
+    ])
+
+    expect(code).toMatchSnapshot()
   })
 
   test('as root node', () => {
-    const code = compile(`<div :id="foo" v-once />`)
+    const { ir, code } = compileWithOnce(`<div :id="foo" v-once />`)
+
+    expect(ir.helpers.size).toBe(0)
+    expect(ir.effect).toEqual([])
+
+    expect(ir.operation).toMatchObject([
+      {
+        type: IRNodeTypes.SET_PROP,
+        element: 1,
+        key: {
+          type: NodeTypes.SIMPLE_EXPRESSION,
+          content: 'id',
+          isStatic: true,
+        },
+        value: {
+          type: NodeTypes.SIMPLE_EXPRESSION,
+          content: 'foo',
+          isStatic: false,
+        },
+      },
+    ])
+
     expect(code).toMatchSnapshot()
     expect(code).not.contains('effect')
   })
+
+  test('on nested plain element', () => {
+    const { ir, code } = compileWithOnce(`<div><div :id="foo" v-once /></div>`)
+    expect(ir.helpers.size).toBe(0)
+    expect(ir.effect).toEqual([])
+
+    expect(ir.operation).toMatchObject([
+      {
+        type: IRNodeTypes.SET_PROP,
+        element: 1,
+        runtimeCamelize: false,
+        key: {
+          type: NodeTypes.SIMPLE_EXPRESSION,
+          content: 'id',
+          isStatic: true,
+        },
+        value: {
+          type: NodeTypes.SIMPLE_EXPRESSION,
+          content: 'foo',
+          isStatic: false,
+        },
+      },
+    ])
+
+    expect(code).toMatchSnapshot()
+  })
+
+  test.todo('on component')
+  test.todo('on slot outlet')
+
+  test('inside v-once', () => {
+    const { ir, code } = compileWithOnce(`<div v-once><div v-once/></div>`)
+    expect(ir.helpers.size).toBe(0)
+    expect(ir.effect).toMatchObject([])
+    expect(ir.operation).toMatchObject([])
+
+    expect(code).toMatchSnapshot()
+  })
+
+  test.todo('with hoistStatic: true')
+  test.todo('with v-if/else')
+  test.todo('with v-for')
 })