diff --git a/packages/vitest/src/node/core.ts b/packages/vitest/src/node/core.ts
index 3d6936dba44e..afc9a8a1fa0b 100644
--- a/packages/vitest/src/node/core.ts
+++ b/packages/vitest/src/node/core.ts
@@ -2,7 +2,6 @@ import type { CancelReason, File } from '@vitest/runner'
 import type { Awaitable } from '@vitest/utils'
 import type { Writable } from 'node:stream'
 import type { ViteDevServer } from 'vite'
-import type { defineWorkspace } from 'vitest/config'
 import type { SerializedCoverageConfig } from '../runtime/config'
 import type { ArgumentsType, ProvidedContext, UserConsoleLog } from '../types/general'
 import type { CliOptions } from './cli/cli-api'
@@ -481,7 +480,7 @@ export class Vitest {
     )
 
     const workspaceModule = await this.import<{
-      default: ReturnType<typeof defineWorkspace>
+      default: TestProjectConfiguration[]
     }>(workspaceConfigPath)
 
     if (!workspaceModule.default || !Array.isArray(workspaceModule.default)) {
diff --git a/packages/vitest/src/node/types/config.ts b/packages/vitest/src/node/types/config.ts
index d1f9f9d6d1d4..d6f42188489c 100644
--- a/packages/vitest/src/node/types/config.ts
+++ b/packages/vitest/src/node/types/config.ts
@@ -1161,6 +1161,7 @@ export interface UserWorkspaceConfig extends ViteUserConfig {
   test?: ProjectConfig
 }
 
+// TODO: remove types when "workspace" support is removed
 export type UserProjectConfigFn = (
   env: ConfigEnv
 ) => UserWorkspaceConfig | Promise<UserWorkspaceConfig>
@@ -1183,6 +1184,3 @@ export type TestProjectConfiguration =
   | TestProjectInlineConfiguration
   | Promise<UserWorkspaceConfig>
   | UserProjectConfigFn
-
-/** @deprecated use `TestProjectConfiguration` instead */
-export type WorkspaceProjectConfiguration = TestProjectConfiguration
diff --git a/packages/vitest/src/public/config.ts b/packages/vitest/src/public/config.ts
index fe2d0191e0a0..e24ef6b419e9 100644
--- a/packages/vitest/src/public/config.ts
+++ b/packages/vitest/src/public/config.ts
@@ -3,10 +3,10 @@ import type { ConfigEnv, UserConfig as ViteUserConfig } from 'vite'
 import type {
   TestProjectConfiguration,
   TestProjectInlineConfiguration,
+  UserConfig,
   UserProjectConfigExport,
   UserProjectConfigFn,
   UserWorkspaceConfig,
-  WorkspaceProjectConfiguration,
 } from '../node/types/config'
 import '../node/types/vite'
 
@@ -23,38 +23,33 @@ export type { WatcherTriggerPattern } from '../node/watcher'
 export { mergeConfig } from 'vite'
 export type { Plugin } from 'vite'
 
-export type { ConfigEnv, ViteUserConfig }
-/**
- * @deprecated Use `ViteUserConfig` instead
- */
-export type UserConfig = ViteUserConfig
+export type { ConfigEnv, UserConfig as TestUserConfig, ViteUserConfig }
 export type {
   TestProjectConfiguration,
   TestProjectInlineConfiguration,
   UserProjectConfigExport,
   UserProjectConfigFn,
   UserWorkspaceConfig,
-  WorkspaceProjectConfiguration,
 }
-export type UserConfigFnObject = (env: ConfigEnv) => ViteUserConfig
-export type UserConfigFnPromise = (env: ConfigEnv) => Promise<ViteUserConfig>
-export type UserConfigFn = (
+export type ViteUserConfigFnObject = (env: ConfigEnv) => ViteUserConfig
+export type ViteUserConfigFnPromise = (env: ConfigEnv) => Promise<ViteUserConfig>
+export type ViteUserConfigFn = (
   env: ConfigEnv
 ) => ViteUserConfig | Promise<ViteUserConfig>
-export type UserConfigExport =
+export type ViteUserConfigExport =
   | ViteUserConfig
   | Promise<ViteUserConfig>
-  | UserConfigFnObject
-  | UserConfigFnPromise
-  | UserConfigFn
+  | ViteUserConfigFnObject
+  | ViteUserConfigFnPromise
+  | ViteUserConfigFn
 
 export function defineConfig(config: ViteUserConfig): ViteUserConfig
 export function defineConfig(
   config: Promise<ViteUserConfig>
 ): Promise<ViteUserConfig>
-export function defineConfig(config: UserConfigFnObject): UserConfigFnObject
-export function defineConfig(config: UserConfigExport): UserConfigExport
-export function defineConfig(config: UserConfigExport): UserConfigExport {
+export function defineConfig(config: ViteUserConfigFnObject): ViteUserConfigFnObject
+export function defineConfig(config: ViteUserConfigExport): ViteUserConfigExport
+export function defineConfig(config: ViteUserConfigExport): ViteUserConfigExport {
   return config
 }
 
@@ -65,10 +60,3 @@ export function defineProject(config: UserProjectConfigExport): UserProjectConfi
 export function defineProject(config: UserProjectConfigExport): UserProjectConfigExport {
   return config
 }
-
-/**
- * @deprecated use the `projects` field in the root config instead
- */
-export function defineWorkspace(config: TestProjectConfiguration[]): TestProjectConfiguration[] {
-  return config
-}
diff --git a/test/cli/fixtures/browser-multiple/vitest.config.ts b/test/cli/fixtures/browser-multiple/vitest.config.ts
index e3e49a772c50..3703112fe1f9 100644
--- a/test/cli/fixtures/browser-multiple/vitest.config.ts
+++ b/test/cli/fixtures/browser-multiple/vitest.config.ts
@@ -1,5 +1,5 @@
 import { resolve } from 'pathe';
-import { defineConfig, defineWorkspace } from 'vitest/config';
+import { defineConfig } from 'vitest/config';
 
 export default defineConfig({
   test: {
diff --git a/test/config/fixtures/pool-isolation/isolated.test.ts b/test/config/fixtures/pool-isolation/isolated.test.ts
index c0a0ab9148b6..a5a3ca6c25b0 100644
--- a/test/config/fixtures/pool-isolation/isolated.test.ts
+++ b/test/config/fixtures/pool-isolation/isolated.test.ts
@@ -1,11 +1,11 @@
 import { expect, test } from 'vitest'
-import type { UserConfig } from 'vitest/config'
+import type { TestUserConfig } from 'vitest/config'
 
 const pool = process.env.TESTED_POOL as "forks" | "threads";
 
 test('is isolated', () => {
   // @ts-expect-error -- internal
-  const config: NonNullable<UserConfig['test']> = globalThis.__vitest_worker__.config
+  const config: TestUserConfig = globalThis.__vitest_worker__.config
 
   if (pool === 'forks') {
     expect(config.poolOptions?.forks?.isolate).toBe(true)
diff --git a/test/config/fixtures/pool-isolation/non-isolated.test.ts b/test/config/fixtures/pool-isolation/non-isolated.test.ts
index 3a6471b9e657..4794c3091df3 100644
--- a/test/config/fixtures/pool-isolation/non-isolated.test.ts
+++ b/test/config/fixtures/pool-isolation/non-isolated.test.ts
@@ -1,11 +1,11 @@
 import { expect, test } from 'vitest'
-import type { UserConfig } from 'vitest/config'
+import type { TestUserConfig } from 'vitest/config'
 
 const pool = process.env.TESTED_POOL as "forks" | "threads";
 
 test('is isolated', () => {
   // @ts-expect-error -- internal
-  const config: NonNullable<UserConfig['test']> = globalThis.__vitest_worker__.config
+  const config: TestUserConfig = globalThis.__vitest_worker__.config
 
   if (pool === 'forks') {
     expect(config.poolOptions?.forks?.isolate).toBe(false)
diff --git a/test/config/fixtures/workspace/browser/workspace-with-browser.ts b/test/config/fixtures/workspace/browser/workspace-with-browser.ts
index 0f3a52dcb9c7..0ec8e172ec22 100644
--- a/test/config/fixtures/workspace/browser/workspace-with-browser.ts
+++ b/test/config/fixtures/workspace/browser/workspace-with-browser.ts
@@ -1,6 +1,5 @@
-import { defineWorkspace } from "vitest/config";
-
-export default defineWorkspace([
+// TODO: remove when --workspace is removed
+export default [
   {
     test: {
       name: "Browser project",
@@ -11,4 +10,4 @@ export default defineWorkspace([
       },
     }
   }
-])
\ No newline at end of file
+]
\ No newline at end of file
diff --git a/test/config/test/config-types.test-d.ts b/test/config/test/config-types.test-d.ts
index 26dd8b4479df..26a335a9a75d 100644
--- a/test/config/test/config-types.test-d.ts
+++ b/test/config/test/config-types.test-d.ts
@@ -1,5 +1,6 @@
+import type { TestUserConfig } from 'vitest/config'
 import { assertType, describe, expectTypeOf, test } from 'vitest'
-import { defineConfig, defineProject, defineWorkspace, mergeConfig } from 'vitest/config'
+import { defineConfig, defineProject, mergeConfig } from 'vitest/config'
 
 const expectMainTestConfig = expectTypeOf(defineConfig).parameter(0).resolves.toHaveProperty('test').exclude<undefined>()
 const expectProjectTestConfig = expectTypeOf(defineProject).parameter(0).resolves.toHaveProperty('test').exclude<undefined>()
@@ -32,7 +33,7 @@ describe('merge config helper', () => {
 })
 
 describe('define workspace helper', () => {
-  type DefineWorkspaceParameter = Parameters<typeof defineWorkspace>[0]
+  type DefineWorkspaceParameter = TestUserConfig['projects']
 
   test('allows string', () => {
     assertType<DefineWorkspaceParameter>(['./path/to/workspace'])
@@ -75,32 +76,4 @@ describe('define workspace helper', () => {
       },
     ])
   })
-
-  test('return type matches parameters', () => {
-    expectTypeOf(defineWorkspace).returns.toMatchTypeOf<DefineWorkspaceParameter>()
-
-    expectTypeOf(defineWorkspace([
-      './path/to/project',
-      {
-        test: {
-          name: 'Workspace Project #1',
-          include: ['string'],
-
-          // @ts-expect-error -- Not allowed here
-          coverage: {},
-        },
-      },
-      './path/to/another/project',
-      {
-        extends: 'workspace custom field',
-        test: {
-          name: 'Workspace Project #2',
-          include: ['string'],
-
-          // @ts-expect-error -- Not allowed here
-          coverage: {},
-        },
-      },
-    ])).items.toMatchTypeOf<DefineWorkspaceParameter[number]>()
-  })
 })
diff --git a/test/core/test/exports.test.ts b/test/core/test/exports.test.ts
index 2fdcfaba75c0..1314e201e74f 100644
--- a/test/core/test/exports.test.ts
+++ b/test/core/test/exports.test.ts
@@ -46,7 +46,6 @@ it('exports snapshot', async ({ skip, task }) => {
           "defaultInclude": "object",
           "defineConfig": "function",
           "defineProject": "function",
-          "defineWorkspace": "function",
           "extraInlineDeps": "object",
           "mergeConfig": "function",
         },
@@ -202,7 +201,6 @@ it('exports snapshot', async ({ skip, task }) => {
             "defaultInclude": "object",
             "defineConfig": "function",
             "defineProject": "function",
-            "defineWorkspace": "function",
             "extraInlineDeps": "object",
             "mergeConfig": "function",
           },
diff --git a/test/coverage-test/vitest.workspace.custom.ts b/test/coverage-test/vitest.workspace.custom.ts
index 4110885484c4..4996b88f92c5 100644
--- a/test/coverage-test/vitest.workspace.custom.ts
+++ b/test/coverage-test/vitest.workspace.custom.ts
@@ -1,4 +1,5 @@
-import { defineConfig, defineWorkspace } from 'vitest/config'
+import type { UserWorkspaceConfig } from 'vitest/config'
+import { defineConfig } from 'vitest/config'
 
 const GENERIC_TESTS = 'test/**.test.ts'
 const V8_TESTS = 'test/**.v8.test.ts'
@@ -14,6 +15,11 @@ const config = defineConfig({
   },
 })
 
+// TODO: move when --workspace is removed
+function defineWorkspace(config: UserWorkspaceConfig[]) {
+  return config
+}
+
 export default defineWorkspace([
   // Test cases for v8-provider
   {
diff --git a/test/snapshots/test/fixtures/workspace/vitest.config.ts b/test/snapshots/test/fixtures/workspace/vitest.config.ts
index d8625728b0f9..45eba408404c 100644
--- a/test/snapshots/test/fixtures/workspace/vitest.config.ts
+++ b/test/snapshots/test/fixtures/workspace/vitest.config.ts
@@ -1,4 +1,4 @@
-import { defineConfig, defineWorkspace } from 'vitest/config'
+import { defineConfig } from 'vitest/config'
 
 export default defineConfig({
   test: {
diff --git a/test/test-utils/index.ts b/test/test-utils/index.ts
index 1095afbc6a9d..fd339c348b3e 100644
--- a/test/test-utils/index.ts
+++ b/test/test-utils/index.ts
@@ -1,7 +1,7 @@
 import type { Options } from 'tinyexec'
 import type { UserConfig as ViteUserConfig } from 'vite'
 import type { WorkerGlobalState } from 'vitest'
-import type { WorkspaceProjectConfiguration } from 'vitest/config'
+import type { TestProjectConfiguration } from 'vitest/config'
 import type { TestModule, UserConfig, Vitest, VitestRunMode } from 'vitest/node'
 import { webcrypto as crypto } from 'node:crypto'
 import fs from 'node:fs'
@@ -277,7 +277,7 @@ export type TestFsStructure = Record<
   string,
   | string
   | ViteUserConfig
-  | WorkspaceProjectConfiguration[]
+  | TestProjectConfiguration[]
   | ((...args: any[]) => unknown)
   | [(...args: any[]) => unknown, { exports?: string[]; imports?: Record<string, string[]> }]
 >
diff --git a/test/workspaces/space-pools/isolate.test.ts b/test/workspaces/space-pools/isolate.test.ts
index f7d730d79155..1742b9042efd 100644
--- a/test/workspaces/space-pools/isolate.test.ts
+++ b/test/workspaces/space-pools/isolate.test.ts
@@ -1,9 +1,9 @@
-import type { UserConfig } from 'vitest/config'
+import type { ViteUserConfig } from 'vitest/config'
 import { expect, test } from 'vitest'
 
 test('is isolated', () => {
   // @ts-expect-error -- internal
-  const config: NonNullable<UserConfig['test']> = globalThis.__vitest_worker__.config
+  const config: NonNullable<ViteUserConfig['test']> = globalThis.__vitest_worker__.config
 
   if (config.pool === 'forks') {
     expect(config.poolOptions?.forks?.isolate).toBe(true)
diff --git a/test/workspaces/space-pools/multi-worker.test.ts b/test/workspaces/space-pools/multi-worker.test.ts
index d793d6d33afe..78d2a723b591 100644
--- a/test/workspaces/space-pools/multi-worker.test.ts
+++ b/test/workspaces/space-pools/multi-worker.test.ts
@@ -1,9 +1,9 @@
-import type { UserConfig } from 'vitest/config'
+import type { ViteUserConfig } from 'vitest/config'
 import { expect, test } from 'vitest'
 
 test('is multi worker', () => {
   // @ts-expect-error -- internal
-  const config: NonNullable<UserConfig['test']> = globalThis.__vitest_worker__.config
+  const config: NonNullable<ViteUserConfig['test']> = globalThis.__vitest_worker__.config
 
   if (config.pool === 'forks') {
     expect(config.poolOptions?.forks?.singleFork).toBe(false)
diff --git a/test/workspaces/space-pools/no-isolate.test.ts b/test/workspaces/space-pools/no-isolate.test.ts
index 99371dfc31d9..bd8822e4834b 100644
--- a/test/workspaces/space-pools/no-isolate.test.ts
+++ b/test/workspaces/space-pools/no-isolate.test.ts
@@ -1,9 +1,9 @@
-import type { UserConfig } from 'vitest/config'
+import type { ViteUserConfig } from 'vitest/config'
 import { expect, test } from 'vitest'
 
 test('is not isolated', () => {
   // @ts-expect-error -- internal
-  const config: NonNullable<UserConfig['test']> = globalThis.__vitest_worker__.config
+  const config: NonNullable<ViteUserConfig['test']> = globalThis.__vitest_worker__.config
 
   if (config.pool === 'forks') {
     expect(config.poolOptions?.forks?.isolate).toBe(false)
diff --git a/test/workspaces/space-pools/single-worker.test.ts b/test/workspaces/space-pools/single-worker.test.ts
index bdba9f30200c..7b754197dff7 100644
--- a/test/workspaces/space-pools/single-worker.test.ts
+++ b/test/workspaces/space-pools/single-worker.test.ts
@@ -1,9 +1,9 @@
-import type { UserConfig } from 'vitest/config'
+import type { ViteUserConfig } from 'vitest/config'
 import { expect, test } from 'vitest'
 
 test('is single worker', () => {
   // @ts-expect-error -- internal
-  const config: NonNullable<UserConfig['test']> = globalThis.__vitest_worker__.config
+  const config: NonNullable<ViteUserConfig['test']> = globalThis.__vitest_worker__.config
 
   if (config.pool === 'forks') {
     expect(config.poolOptions?.forks?.singleFork).toBe(true)