diff --git a/.changeset/tender-carrots-sniff.md b/.changeset/tender-carrots-sniff.md
new file mode 100644
index 000000000..d30f6da7d
--- /dev/null
+++ b/.changeset/tender-carrots-sniff.md
@@ -0,0 +1,5 @@
+---
+'preact-cli': patch
+---
+
+Ensuring the sw flag is a boolean in watch mode
diff --git a/packages/cli/lib/commands/build.js b/packages/cli/lib/commands/build.js
index 2d8d4d821..2745ccda9 100644
--- a/packages/cli/lib/commands/build.js
+++ b/packages/cli/lib/commands/build.js
@@ -2,10 +2,9 @@ const rimraf = require('rimraf');
 const { resolve } = require('path');
 const { promisify } = require('util');
 const runWebpack = require('../lib/webpack/run-webpack');
+const { toBool } = require('../util');
 const { validateArgs } = require('./validate-args');
 
-const toBool = val => val === void 0 || (val === 'false' ? false : val);
-
 const options = [
 	{
 		name: '--src',
diff --git a/packages/cli/lib/commands/watch.js b/packages/cli/lib/commands/watch.js
index 37b683b3c..0ccc6dcdd 100644
--- a/packages/cli/lib/commands/watch.js
+++ b/packages/cli/lib/commands/watch.js
@@ -1,5 +1,5 @@
 const runWebpack = require('../lib/webpack/run-webpack');
-const { warn } = require('../util');
+const { toBool, warn } = require('../util');
 const { validateArgs } = require('./validate-args');
 
 const options = [
@@ -101,6 +101,7 @@ async function command(src, argv) {
 	}
 	argv.src = src || argv.src;
 	argv.production = false;
+	argv.sw = toBool(argv.sw);
 
 	if (argv.https || process.env.HTTPS) {
 		let { key, cert, cacert } = argv;
diff --git a/packages/cli/lib/util.js b/packages/cli/lib/util.js
index f7c3f5150..6856c165f 100644
--- a/packages/cli/lib/util.js
+++ b/packages/cli/lib/util.js
@@ -50,3 +50,7 @@ exports.normalizeTemplatesResponse = function (repos = []) {
 		description: repo.description || '',
 	}));
 };
+
+exports.toBool = function (val) {
+	return val === void 0 || (val === 'false' ? false : val);
+};