diff --git a/doc/api/cli.md b/doc/api/cli.md
index c99d02fc9394ee..f712b9c9a98981 100644
--- a/doc/api/cli.md
+++ b/doc/api/cli.md
@@ -460,6 +460,10 @@ added:
   - v13.3.0
   - v12.16.0
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/47286
+    description: This option is no longer required as WASI is
+                 enabled by default, but can still be passed.
   - version: v13.6.0
     pr-url: https://github.com/nodejs/node/pull/30980
     description: changed from `--experimental-wasi-unstable-preview0` to
diff --git a/doc/api/wasi.md b/doc/api/wasi.md
index ac395b70894c99..f70470d8dc0732 100644
--- a/doc/api/wasi.md
+++ b/doc/api/wasi.md
@@ -97,9 +97,6 @@ Use [wabt](https://github.com/WebAssembly/wabt) to compile `.wat` to `.wasm`
 $ wat2wasm demo.wat
 ```
 
-The `--experimental-wasi-unstable-preview1` CLI argument is needed for this
-example to run.
-
 ## Class: `WASI`
 
 <!-- YAML
diff --git a/doc/node.1 b/doc/node.1
index 114549710f81fa..62ce3d7d963a6d 100644
--- a/doc/node.1
+++ b/doc/node.1
@@ -179,7 +179,8 @@ Disable top-level await keyword support in REPL.
 Enable experimental ES module support in VM module.
 .
 .It Fl -experimental-wasi-unstable-preview1
-Enable experimental WebAssembly System Interface support.
+Enable experimental WebAssembly System Interface support. This
+flag is no longer required as WASI is enabled by default.
 .
 .It Fl -experimental-wasm-modules
 Enable experimental WebAssembly module support.
diff --git a/lib/internal/process/pre_execution.js b/lib/internal/process/pre_execution.js
index 3e599b39403e4a..d6e99aad3ae5d2 100644
--- a/lib/internal/process/pre_execution.js
+++ b/lib/internal/process/pre_execution.js
@@ -73,7 +73,6 @@ function prepareExecution(options) {
   initializeReport();
   initializeSourceMapsHandlers();
   initializeDeprecations();
-  initializeWASI();
 
   require('internal/dns/utils').initializeDns();
 
@@ -548,13 +547,6 @@ function readPolicyFromDisk() {
   }
 }
 
-function initializeWASI() {
-  const { BuiltinModule } = require('internal/bootstrap/loaders');
-  const mod = BuiltinModule.map.get('wasi');
-  mod.canBeRequiredByUsers =
-    getOptionValue('--experimental-wasi-unstable-preview1');
-}
-
 function initializeCJSLoader() {
   const { initializeCJS } = require('internal/modules/cjs/loader');
   initializeCJS();
diff --git a/src/node_options.cc b/src/node_options.cc
index b8685530965c2e..a0a1baae9e77d0 100644
--- a/src/node_options.cc
+++ b/src/node_options.cc
@@ -426,10 +426,8 @@ EnvironmentOptionsParser::EnvironmentOptionsParser() {
             kAllowedInEnvvar);
   AddOption("--experimental-worker", "", NoOp{}, kAllowedInEnvvar);
   AddOption("--experimental-report", "", NoOp{}, kAllowedInEnvvar);
-  AddOption("--experimental-wasi-unstable-preview1",
-            "experimental WASI support",
-            &EnvironmentOptions::experimental_wasi,
-            kAllowedInEnvvar);
+  AddOption(
+      "--experimental-wasi-unstable-preview1", "", NoOp{}, kAllowedInEnvvar);
   AddOption("--expose-internals", "", &EnvironmentOptions::expose_internals);
   AddOption("--frozen-intrinsics",
             "experimental frozen intrinsics support",
diff --git a/src/node_options.h b/src/node_options.h
index 07ec47d861c77f..85308e2c2e3c24 100644
--- a/src/node_options.h
+++ b/src/node_options.h
@@ -185,7 +185,6 @@ class EnvironmentOptions : public Options {
 
   bool syntax_check_only = false;
   bool has_eval_string = false;
-  bool experimental_wasi = false;
   std::string eval_string;
   bool print_eval = false;
   bool force_repl = false;
diff --git a/test/parallel/test-repl-built-in-modules.js b/test/parallel/test-repl-built-in-modules.js
deleted file mode 100644
index 6273367e65a2a7..00000000000000
--- a/test/parallel/test-repl-built-in-modules.js
+++ /dev/null
@@ -1,48 +0,0 @@
-'use strict';
-
-require('../common');
-const assert = require('assert');
-const cp = require('child_process');
-
-function runREPLWithAdditionalFlags(flags) {
-  // Use -i to force node into interactive mode, despite stdout not being a TTY
-  const args = ['-i'].concat(flags);
-  const ret = cp.execFileSync(process.execPath, args, {
-    input: 'require(\'events\');\nrequire(\'wasi\');',
-    encoding: 'utf8',
-  });
-  return ret;
-}
-
-// Run REPL in normal mode.
-let stdout = runREPLWithAdditionalFlags([]);
-assert.match(stdout, /\[Function: EventEmitter\] {/);
-assert.match(
-  stdout,
-  /Uncaught Error: Cannot find module 'wasi'[\w\W]+- <repl>\n/);
-
-// Run REPL with '--experimental-wasi-unstable-preview1'
-stdout = runREPLWithAdditionalFlags([
-  '--experimental-wasi-unstable-preview1',
-]);
-assert.match(stdout, /\[Function: EventEmitter\] {/);
-assert.doesNotMatch(
-  stdout,
-  /Uncaught Error: Cannot find module 'wasi'[\w\W]+- <repl>\n/);
-assert.match(stdout, /{ WASI: \[class WASI\] }/);
-
-{
-  const res = cp.execFileSync(process.execPath, ['-i'], {
-    input: "'wasi' in global",
-    encoding: 'utf8',
-  });
-  // `wasi` shouldn't be defined on global when the flag is not set
-  assert.match(res, /false\n/);
-}
-{
-  const res = cp.execFileSync(process.execPath, ['-i', '--experimental-wasi-unstable-preview1'], {
-    input: "'wasi' in global",
-    encoding: 'utf8',
-  });
-  assert.match(res, /true\n/);
-}
diff --git a/test/wasi/test-return-on-exit.js b/test/wasi/test-return-on-exit.js
index e61f4174c3d4ee..3956ee02066f27 100644
--- a/test/wasi/test-return-on-exit.js
+++ b/test/wasi/test-return-on-exit.js
@@ -1,4 +1,3 @@
-// Flags: --experimental-wasi-unstable-preview1
 'use strict';
 const common = require('../common');
 const assert = require('assert');
diff --git a/test/wasi/test-wasi-initialize-validation.js b/test/wasi/test-wasi-initialize-validation.js
index f1279a6009433d..11464dcf35229d 100644
--- a/test/wasi/test-wasi-initialize-validation.js
+++ b/test/wasi/test-wasi-initialize-validation.js
@@ -1,4 +1,3 @@
-// Flags: --experimental-wasi-unstable-preview1
 'use strict';
 
 const common = require('../common');
diff --git a/test/wasi/test-wasi-not-started.js b/test/wasi/test-wasi-not-started.js
index 28da4fa41b657f..fac42ae193deee 100644
--- a/test/wasi/test-wasi-not-started.js
+++ b/test/wasi/test-wasi-not-started.js
@@ -28,7 +28,6 @@ if (process.argv[2] === 'wasi-child') {
   const cp = require('child_process');
 
   const child = cp.spawnSync(process.execPath, [
-    '--experimental-wasi-unstable-preview1',
     __filename,
     'wasi-child',
   ], {
diff --git a/test/wasi/test-wasi-options-validation.js b/test/wasi/test-wasi-options-validation.js
index 20d7663c0d0c5f..4beb5e8f52a4fb 100644
--- a/test/wasi/test-wasi-options-validation.js
+++ b/test/wasi/test-wasi-options-validation.js
@@ -1,7 +1,5 @@
 'use strict';
 
-// Flags: --experimental-wasi-unstable-preview1
-
 require('../common');
 const assert = require('assert');
 const { WASI } = require('wasi');
diff --git a/test/wasi/test-wasi-require-flag.js b/test/wasi/test-wasi-require-flag.js
deleted file mode 100644
index 0a52ea952d2785..00000000000000
--- a/test/wasi/test-wasi-require-flag.js
+++ /dev/null
@@ -1,9 +0,0 @@
-'use strict';
-// This test verifies that the WASI module cannot be require()'ed without a
-// CLI flag while it is still experimental.
-require('../common');
-const assert = require('assert');
-
-assert.throws(() => {
-  require('wasi');
-}, /^Error: Cannot find module 'wasi'/);
diff --git a/test/wasi/test-wasi-start-validation.js b/test/wasi/test-wasi-start-validation.js
index 01bd1a2bb63624..d856c5c0b8f19c 100644
--- a/test/wasi/test-wasi-start-validation.js
+++ b/test/wasi/test-wasi-start-validation.js
@@ -1,4 +1,3 @@
-// Flags: --experimental-wasi-unstable-preview1
 'use strict';
 
 const common = require('../common');
diff --git a/test/wasi/test-wasi-stdio.js b/test/wasi/test-wasi-stdio.js
index 90ab7caa831c1e..83b9beff8dcfe7 100644
--- a/test/wasi/test-wasi-stdio.js
+++ b/test/wasi/test-wasi-stdio.js
@@ -1,4 +1,3 @@
-// Flags: --experimental-wasi-unstable-preview1
 'use strict';
 const common = require('../common');
 const tmpdir = require('../common/tmpdir');
diff --git a/test/wasi/test-wasi-symlinks.js b/test/wasi/test-wasi-symlinks.js
index 7f6d9302dedf0a..339c33db22b068 100644
--- a/test/wasi/test-wasi-symlinks.js
+++ b/test/wasi/test-wasi-symlinks.js
@@ -63,7 +63,6 @@ if (process.argv[2] === 'wasi-child') {
     console.log('executing', options.test);
     const opts = { env: { ...process.env, NODE_DEBUG_NATIVE: 'wasi' } };
     const child = cp.spawnSync(process.execPath, [
-      '--experimental-wasi-unstable-preview1',
       __filename,
       'wasi-child',
       options.test,
diff --git a/test/wasi/test-wasi-worker-terminate.js b/test/wasi/test-wasi-worker-terminate.js
index a0851e14ad6b62..29657f003ba62c 100644
--- a/test/wasi/test-wasi-worker-terminate.js
+++ b/test/wasi/test-wasi-worker-terminate.js
@@ -1,4 +1,3 @@
-// Flags: --experimental-wasi-unstable-preview1
 'use strict';
 
 const common = require('../common');
diff --git a/test/wasi/test-wasi.js b/test/wasi/test-wasi.js
index b9f7cb9be7b2c6..2ddc4290352a20 100644
--- a/test/wasi/test-wasi.js
+++ b/test/wasi/test-wasi.js
@@ -88,7 +88,6 @@ if (process.argv[2] === 'wasi-child-default') {
 
     const child = cp.spawnSync(process.execPath, [
       ...args,
-      '--experimental-wasi-unstable-preview1',
       __filename,
       'wasi-child-' + flavor,
       options.test,