diff --git a/.eslintignore b/.eslintignore
index 6791fbf312a08b..ceca2031c11e27 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -1,5 +1,5 @@
 lib/internal/v8_prof_polyfill.js
-lib/punycode.js
+lib/internal/punycode.js
 test/addons/??_*/
 test/fixtures
 test/disabled
diff --git a/doc/api/punycode.md b/doc/api/punycode.md
index d34b3fdf2a1fa2..97332d4ce6e418 100644
--- a/doc/api/punycode.md
+++ b/doc/api/punycode.md
@@ -1,6 +1,6 @@
 # punycode
 
-    Stability: 2 - Stable
+    Stability: 0 - Deprecated
 
 The `punycode` module is a bundled version of the [Punycode.js][] module. It
 can be accessed using:
diff --git a/lib/internal/punycode.js b/lib/internal/punycode.js
new file mode 100644
index 00000000000000..9d788aefb59087
--- /dev/null
+++ b/lib/internal/punycode.js
@@ -0,0 +1,440 @@
+'use strict';
+
+/** Highest positive signed 32-bit float value */
+const maxInt = 2147483647; // aka. 0x7FFFFFFF or 2^31-1
+
+/** Bootstring parameters */
+const base = 36;
+const tMin = 1;
+const tMax = 26;
+const skew = 38;
+const damp = 700;
+const initialBias = 72;
+const initialN = 128; // 0x80
+const delimiter = '-'; // '\x2D'
+
+/** Regular expressions */
+const regexPunycode = /^xn--/;
+const regexNonASCII = /[^\x20-\x7E]/; // unprintable ASCII chars + non-ASCII chars
+const regexSeparators = /[\x2E\u3002\uFF0E\uFF61]/g; // RFC 3490 separators
+
+/** Error messages */
+const errors = {
+	'overflow': 'Overflow: input needs wider integers to process',
+	'not-basic': 'Illegal input >= 0x80 (not a basic code point)',
+	'invalid-input': 'Invalid input'
+};
+
+/** Convenience shortcuts */
+const baseMinusTMin = base - tMin;
+const floor = Math.floor;
+const stringFromCharCode = String.fromCharCode;
+
+/*--------------------------------------------------------------------------*/
+
+/**
+ * A generic error utility function.
+ * @private
+ * @param {String} type The error type.
+ * @returns {Error} Throws a `RangeError` with the applicable error message.
+ */
+function error(type) {
+	throw new RangeError(errors[type]);
+}
+
+/**
+ * A generic `Array#map` utility function.
+ * @private
+ * @param {Array} array The array to iterate over.
+ * @param {Function} callback The function that gets called for every array
+ * item.
+ * @returns {Array} A new array of values returned by the callback function.
+ */
+function map(array, fn) {
+	const result = [];
+	let length = array.length;
+	while (length--) {
+		result[length] = fn(array[length]);
+	}
+	return result;
+}
+
+/**
+ * A simple `Array#map`-like wrapper to work with domain name strings or email
+ * addresses.
+ * @private
+ * @param {String} domain The domain name or email address.
+ * @param {Function} callback The function that gets called for every
+ * character.
+ * @returns {Array} A new string of characters returned by the callback
+ * function.
+ */
+function mapDomain(string, fn) {
+	const parts = string.split('@');
+	let result = '';
+	if (parts.length > 1) {
+		// In email addresses, only the domain name should be punycoded. Leave
+		// the local part (i.e. everything up to `@`) intact.
+		result = parts[0] + '@';
+		string = parts[1];
+	}
+	// Avoid `split(regex)` for IE8 compatibility. See #17.
+	string = string.replace(regexSeparators, '\x2E');
+	const labels = string.split('.');
+	const encoded = map(labels, fn).join('.');
+	return result + encoded;
+}
+
+/**
+ * Creates an array containing the numeric code points of each Unicode
+ * character in the string. While JavaScript uses UCS-2 internally,
+ * this function will convert a pair of surrogate halves (each of which
+ * UCS-2 exposes as separate characters) into a single code point,
+ * matching UTF-16.
+ * @see `punycode.ucs2.encode`
+ * @see <https://mathiasbynens.be/notes/javascript-encoding>
+ * @memberOf punycode.ucs2
+ * @name decode
+ * @param {String} string The Unicode input string (UCS-2).
+ * @returns {Array} The new array of code points.
+ */
+function ucs2decode(string) {
+	const output = [];
+	let counter = 0;
+	const length = string.length;
+	while (counter < length) {
+		const value = string.charCodeAt(counter++);
+		if (value >= 0xD800 && value <= 0xDBFF && counter < length) {
+			// It's a high surrogate, and there is a next character.
+			const extra = string.charCodeAt(counter++);
+			if ((extra & 0xFC00) == 0xDC00) { // Low surrogate.
+				output.push(((value & 0x3FF) << 10) + (extra & 0x3FF) + 0x10000);
+			} else {
+				// It's an unmatched surrogate; only append this code unit, in case the
+				// next code unit is the high surrogate of a surrogate pair.
+				output.push(value);
+				counter--;
+			}
+		} else {
+			output.push(value);
+		}
+	}
+	return output;
+}
+
+/**
+ * Creates a string based on an array of numeric code points.
+ * @see `punycode.ucs2.decode`
+ * @memberOf punycode.ucs2
+ * @name encode
+ * @param {Array} codePoints The array of numeric code points.
+ * @returns {String} The new Unicode string (UCS-2).
+ */
+const ucs2encode = array => String.fromCodePoint(...array);
+
+/**
+ * Converts a basic code point into a digit/integer.
+ * @see `digitToBasic()`
+ * @private
+ * @param {Number} codePoint The basic numeric code point value.
+ * @returns {Number} The numeric value of a basic code point (for use in
+ * representing integers) in the range `0` to `base - 1`, or `base` if
+ * the code point does not represent a value.
+ */
+const basicToDigit = function(codePoint) {
+	if (codePoint - 0x30 < 0x0A) {
+		return codePoint - 0x16;
+	}
+	if (codePoint - 0x41 < 0x1A) {
+		return codePoint - 0x41;
+	}
+	if (codePoint - 0x61 < 0x1A) {
+		return codePoint - 0x61;
+	}
+	return base;
+};
+
+/**
+ * Converts a digit/integer into a basic code point.
+ * @see `basicToDigit()`
+ * @private
+ * @param {Number} digit The numeric value of a basic code point.
+ * @returns {Number} The basic code point whose value (when used for
+ * representing integers) is `digit`, which needs to be in the range
+ * `0` to `base - 1`. If `flag` is non-zero, the uppercase form is
+ * used; else, the lowercase form is used. The behavior is undefined
+ * if `flag` is non-zero and `digit` has no uppercase form.
+ */
+const digitToBasic = function(digit, flag) {
+	//  0..25 map to ASCII a..z or A..Z
+	// 26..35 map to ASCII 0..9
+	return digit + 22 + 75 * (digit < 26) - ((flag != 0) << 5);
+};
+
+/**
+ * Bias adaptation function as per section 3.4 of RFC 3492.
+ * https://tools.ietf.org/html/rfc3492#section-3.4
+ * @private
+ */
+const adapt = function(delta, numPoints, firstTime) {
+	let k = 0;
+	delta = firstTime ? floor(delta / damp) : delta >> 1;
+	delta += floor(delta / numPoints);
+	for (/* no initialization */; delta > baseMinusTMin * tMax >> 1; k += base) {
+		delta = floor(delta / baseMinusTMin);
+	}
+	return floor(k + (baseMinusTMin + 1) * delta / (delta + skew));
+};
+
+/**
+ * Converts a Punycode string of ASCII-only symbols to a string of Unicode
+ * symbols.
+ * @memberOf punycode
+ * @param {String} input The Punycode string of ASCII-only symbols.
+ * @returns {String} The resulting string of Unicode symbols.
+ */
+const decode = function(input) {
+	// Don't use UCS-2.
+	const output = [];
+	const inputLength = input.length;
+	let i = 0;
+	let n = initialN;
+	let bias = initialBias;
+
+	// Handle the basic code points: let `basic` be the number of input code
+	// points before the last delimiter, or `0` if there is none, then copy
+	// the first basic code points to the output.
+
+	let basic = input.lastIndexOf(delimiter);
+	if (basic < 0) {
+		basic = 0;
+	}
+
+	for (let j = 0; j < basic; ++j) {
+		// if it's not a basic code point
+		if (input.charCodeAt(j) >= 0x80) {
+			error('not-basic');
+		}
+		output.push(input.charCodeAt(j));
+	}
+
+	// Main decoding loop: start just after the last delimiter if any basic code
+	// points were copied; start at the beginning otherwise.
+
+	for (let index = basic > 0 ? basic + 1 : 0; index < inputLength; /* no final expression */) {
+
+		// `index` is the index of the next character to be consumed.
+		// Decode a generalized variable-length integer into `delta`,
+		// which gets added to `i`. The overflow checking is easier
+		// if we increase `i` as we go, then subtract off its starting
+		// value at the end to obtain `delta`.
+		let oldi = i;
+		for (let w = 1, k = base; /* no condition */; k += base) {
+
+			if (index >= inputLength) {
+				error('invalid-input');
+			}
+
+			const digit = basicToDigit(input.charCodeAt(index++));
+
+			if (digit >= base || digit > floor((maxInt - i) / w)) {
+				error('overflow');
+			}
+
+			i += digit * w;
+			const t = k <= bias ? tMin : (k >= bias + tMax ? tMax : k - bias);
+
+			if (digit < t) {
+				break;
+			}
+
+			const baseMinusT = base - t;
+			if (w > floor(maxInt / baseMinusT)) {
+				error('overflow');
+			}
+
+			w *= baseMinusT;
+
+		}
+
+		const out = output.length + 1;
+		bias = adapt(i - oldi, out, oldi == 0);
+
+		// `i` was supposed to wrap around from `out` to `0`,
+		// incrementing `n` each time, so we'll fix that now:
+		if (floor(i / out) > maxInt - n) {
+			error('overflow');
+		}
+
+		n += floor(i / out);
+		i %= out;
+
+		// Insert `n` at position `i` of the output.
+		output.splice(i++, 0, n);
+
+	}
+
+	return String.fromCodePoint(...output);
+};
+
+/**
+ * Converts a string of Unicode symbols (e.g. a domain name label) to a
+ * Punycode string of ASCII-only symbols.
+ * @memberOf punycode
+ * @param {String} input The string of Unicode symbols.
+ * @returns {String} The resulting Punycode string of ASCII-only symbols.
+ */
+const encode = function(input) {
+	const output = [];
+
+	// Convert the input in UCS-2 to an array of Unicode code points.
+	input = ucs2decode(input);
+
+	// Cache the length.
+	let inputLength = input.length;
+
+	// Initialize the state.
+	let n = initialN;
+	let delta = 0;
+	let bias = initialBias;
+
+	// Handle the basic code points.
+	for (const currentValue of input) {
+		if (currentValue < 0x80) {
+			output.push(stringFromCharCode(currentValue));
+		}
+	}
+
+	let basicLength = output.length;
+	let handledCPCount = basicLength;
+
+	// `handledCPCount` is the number of code points that have been handled;
+	// `basicLength` is the number of basic code points.
+
+	// Finish the basic string with a delimiter unless it's empty.
+	if (basicLength) {
+		output.push(delimiter);
+	}
+
+	// Main encoding loop:
+	while (handledCPCount < inputLength) {
+
+		// All non-basic code points < n have been handled already. Find the next
+		// larger one:
+		let m = maxInt;
+		for (const currentValue of input) {
+			if (currentValue >= n && currentValue < m) {
+				m = currentValue;
+			}
+		}
+
+		// Increase `delta` enough to advance the decoder's <n,i> state to <m,0>,
+		// but guard against overflow.
+		const handledCPCountPlusOne = handledCPCount + 1;
+		if (m - n > floor((maxInt - delta) / handledCPCountPlusOne)) {
+			error('overflow');
+		}
+
+		delta += (m - n) * handledCPCountPlusOne;
+		n = m;
+
+		for (const currentValue of input) {
+			if (currentValue < n && ++delta > maxInt) {
+				error('overflow');
+			}
+			if (currentValue == n) {
+				// Represent delta as a generalized variable-length integer.
+				let q = delta;
+				for (let k = base; /* no condition */; k += base) {
+					const t = k <= bias ? tMin : (k >= bias + tMax ? tMax : k - bias);
+					if (q < t) {
+						break;
+					}
+					const qMinusT = q - t;
+					const baseMinusT = base - t;
+					output.push(
+						stringFromCharCode(digitToBasic(t + qMinusT % baseMinusT, 0))
+					);
+					q = floor(qMinusT / baseMinusT);
+				}
+
+				output.push(stringFromCharCode(digitToBasic(q, 0)));
+				bias = adapt(delta, handledCPCountPlusOne, handledCPCount == basicLength);
+				delta = 0;
+				++handledCPCount;
+			}
+		}
+
+		++delta;
+		++n;
+
+	}
+	return output.join('');
+};
+
+/**
+ * Converts a Punycode string representing a domain name or an email address
+ * to Unicode. Only the Punycoded parts of the input will be converted, i.e.
+ * it doesn't matter if you call it on a string that has already been
+ * converted to Unicode.
+ * @memberOf punycode
+ * @param {String} input The Punycoded domain name or email address to
+ * convert to Unicode.
+ * @returns {String} The Unicode representation of the given Punycode
+ * string.
+ */
+const toUnicode = function(input) {
+	return mapDomain(input, function(string) {
+		return regexPunycode.test(string)
+			? decode(string.slice(4).toLowerCase())
+			: string;
+	});
+};
+
+/**
+ * Converts a Unicode string representing a domain name or an email address to
+ * Punycode. Only the non-ASCII parts of the domain name will be converted,
+ * i.e. it doesn't matter if you call it with a domain that's already in
+ * ASCII.
+ * @memberOf punycode
+ * @param {String} input The domain name or email address to convert, as a
+ * Unicode string.
+ * @returns {String} The Punycode representation of the given domain name or
+ * email address.
+ */
+const toASCII = function(input) {
+	return mapDomain(input, function(string) {
+		return regexNonASCII.test(string)
+			? 'xn--' + encode(string)
+			: string;
+	});
+};
+
+/*--------------------------------------------------------------------------*/
+
+/** Define the public API */
+const punycode = {
+	/**
+	 * A string representing the current Punycode.js version number.
+	 * @memberOf punycode
+	 * @type String
+	 */
+	'version': '2.0.0',
+	/**
+	 * An object of methods to convert from JavaScript's internal character
+	 * representation (UCS-2) to Unicode code points, and back.
+	 * @see <https://mathiasbynens.be/notes/javascript-encoding>
+	 * @memberOf punycode
+	 * @type Object
+	 */
+	'ucs2': {
+		'decode': ucs2decode,
+		'encode': ucs2encode
+	},
+	'decode': decode,
+	'encode': encode,
+	'toASCII': toASCII,
+	'toUnicode': toUnicode
+};
+
+module.exports = punycode;
diff --git a/lib/punycode.js b/lib/punycode.js
index 9d788aefb59087..09d29b65323ed0 100644
--- a/lib/punycode.js
+++ b/lib/punycode.js
@@ -1,440 +1,12 @@
 'use strict';
 
-/** Highest positive signed 32-bit float value */
-const maxInt = 2147483647; // aka. 0x7FFFFFFF or 2^31-1
+module.exports = require('internal/punycode');
 
-/** Bootstring parameters */
-const base = 36;
-const tMin = 1;
-const tMax = 26;
-const skew = 38;
-const damp = 700;
-const initialBias = 72;
-const initialN = 128; // 0x80
-const delimiter = '-'; // '\x2D'
+const config = process.binding('config');
 
-/** Regular expressions */
-const regexPunycode = /^xn--/;
-const regexNonASCII = /[^\x20-\x7E]/; // unprintable ASCII chars + non-ASCII chars
-const regexSeparators = /[\x2E\u3002\uFF0E\uFF61]/g; // RFC 3490 separators
-
-/** Error messages */
-const errors = {
-	'overflow': 'Overflow: input needs wider integers to process',
-	'not-basic': 'Illegal input >= 0x80 (not a basic code point)',
-	'invalid-input': 'Invalid input'
-};
-
-/** Convenience shortcuts */
-const baseMinusTMin = base - tMin;
-const floor = Math.floor;
-const stringFromCharCode = String.fromCharCode;
-
-/*--------------------------------------------------------------------------*/
-
-/**
- * A generic error utility function.
- * @private
- * @param {String} type The error type.
- * @returns {Error} Throws a `RangeError` with the applicable error message.
- */
-function error(type) {
-	throw new RangeError(errors[type]);
-}
-
-/**
- * A generic `Array#map` utility function.
- * @private
- * @param {Array} array The array to iterate over.
- * @param {Function} callback The function that gets called for every array
- * item.
- * @returns {Array} A new array of values returned by the callback function.
- */
-function map(array, fn) {
-	const result = [];
-	let length = array.length;
-	while (length--) {
-		result[length] = fn(array[length]);
-	}
-	return result;
-}
-
-/**
- * A simple `Array#map`-like wrapper to work with domain name strings or email
- * addresses.
- * @private
- * @param {String} domain The domain name or email address.
- * @param {Function} callback The function that gets called for every
- * character.
- * @returns {Array} A new string of characters returned by the callback
- * function.
- */
-function mapDomain(string, fn) {
-	const parts = string.split('@');
-	let result = '';
-	if (parts.length > 1) {
-		// In email addresses, only the domain name should be punycoded. Leave
-		// the local part (i.e. everything up to `@`) intact.
-		result = parts[0] + '@';
-		string = parts[1];
-	}
-	// Avoid `split(regex)` for IE8 compatibility. See #17.
-	string = string.replace(regexSeparators, '\x2E');
-	const labels = string.split('.');
-	const encoded = map(labels, fn).join('.');
-	return result + encoded;
-}
-
-/**
- * Creates an array containing the numeric code points of each Unicode
- * character in the string. While JavaScript uses UCS-2 internally,
- * this function will convert a pair of surrogate halves (each of which
- * UCS-2 exposes as separate characters) into a single code point,
- * matching UTF-16.
- * @see `punycode.ucs2.encode`
- * @see <https://mathiasbynens.be/notes/javascript-encoding>
- * @memberOf punycode.ucs2
- * @name decode
- * @param {String} string The Unicode input string (UCS-2).
- * @returns {Array} The new array of code points.
- */
-function ucs2decode(string) {
-	const output = [];
-	let counter = 0;
-	const length = string.length;
-	while (counter < length) {
-		const value = string.charCodeAt(counter++);
-		if (value >= 0xD800 && value <= 0xDBFF && counter < length) {
-			// It's a high surrogate, and there is a next character.
-			const extra = string.charCodeAt(counter++);
-			if ((extra & 0xFC00) == 0xDC00) { // Low surrogate.
-				output.push(((value & 0x3FF) << 10) + (extra & 0x3FF) + 0x10000);
-			} else {
-				// It's an unmatched surrogate; only append this code unit, in case the
-				// next code unit is the high surrogate of a surrogate pair.
-				output.push(value);
-				counter--;
-			}
-		} else {
-			output.push(value);
-		}
-	}
-	return output;
+if (config.hasIntl) {
+  const util = require('internal/util');
+  util.printDeprecationMessage(
+    'The punycode module in core is deprecated. Please use the userland ' +
+    '"punycode" module instead (`npm install punycode`).');
 }
-
-/**
- * Creates a string based on an array of numeric code points.
- * @see `punycode.ucs2.decode`
- * @memberOf punycode.ucs2
- * @name encode
- * @param {Array} codePoints The array of numeric code points.
- * @returns {String} The new Unicode string (UCS-2).
- */
-const ucs2encode = array => String.fromCodePoint(...array);
-
-/**
- * Converts a basic code point into a digit/integer.
- * @see `digitToBasic()`
- * @private
- * @param {Number} codePoint The basic numeric code point value.
- * @returns {Number} The numeric value of a basic code point (for use in
- * representing integers) in the range `0` to `base - 1`, or `base` if
- * the code point does not represent a value.
- */
-const basicToDigit = function(codePoint) {
-	if (codePoint - 0x30 < 0x0A) {
-		return codePoint - 0x16;
-	}
-	if (codePoint - 0x41 < 0x1A) {
-		return codePoint - 0x41;
-	}
-	if (codePoint - 0x61 < 0x1A) {
-		return codePoint - 0x61;
-	}
-	return base;
-};
-
-/**
- * Converts a digit/integer into a basic code point.
- * @see `basicToDigit()`
- * @private
- * @param {Number} digit The numeric value of a basic code point.
- * @returns {Number} The basic code point whose value (when used for
- * representing integers) is `digit`, which needs to be in the range
- * `0` to `base - 1`. If `flag` is non-zero, the uppercase form is
- * used; else, the lowercase form is used. The behavior is undefined
- * if `flag` is non-zero and `digit` has no uppercase form.
- */
-const digitToBasic = function(digit, flag) {
-	//  0..25 map to ASCII a..z or A..Z
-	// 26..35 map to ASCII 0..9
-	return digit + 22 + 75 * (digit < 26) - ((flag != 0) << 5);
-};
-
-/**
- * Bias adaptation function as per section 3.4 of RFC 3492.
- * https://tools.ietf.org/html/rfc3492#section-3.4
- * @private
- */
-const adapt = function(delta, numPoints, firstTime) {
-	let k = 0;
-	delta = firstTime ? floor(delta / damp) : delta >> 1;
-	delta += floor(delta / numPoints);
-	for (/* no initialization */; delta > baseMinusTMin * tMax >> 1; k += base) {
-		delta = floor(delta / baseMinusTMin);
-	}
-	return floor(k + (baseMinusTMin + 1) * delta / (delta + skew));
-};
-
-/**
- * Converts a Punycode string of ASCII-only symbols to a string of Unicode
- * symbols.
- * @memberOf punycode
- * @param {String} input The Punycode string of ASCII-only symbols.
- * @returns {String} The resulting string of Unicode symbols.
- */
-const decode = function(input) {
-	// Don't use UCS-2.
-	const output = [];
-	const inputLength = input.length;
-	let i = 0;
-	let n = initialN;
-	let bias = initialBias;
-
-	// Handle the basic code points: let `basic` be the number of input code
-	// points before the last delimiter, or `0` if there is none, then copy
-	// the first basic code points to the output.
-
-	let basic = input.lastIndexOf(delimiter);
-	if (basic < 0) {
-		basic = 0;
-	}
-
-	for (let j = 0; j < basic; ++j) {
-		// if it's not a basic code point
-		if (input.charCodeAt(j) >= 0x80) {
-			error('not-basic');
-		}
-		output.push(input.charCodeAt(j));
-	}
-
-	// Main decoding loop: start just after the last delimiter if any basic code
-	// points were copied; start at the beginning otherwise.
-
-	for (let index = basic > 0 ? basic + 1 : 0; index < inputLength; /* no final expression */) {
-
-		// `index` is the index of the next character to be consumed.
-		// Decode a generalized variable-length integer into `delta`,
-		// which gets added to `i`. The overflow checking is easier
-		// if we increase `i` as we go, then subtract off its starting
-		// value at the end to obtain `delta`.
-		let oldi = i;
-		for (let w = 1, k = base; /* no condition */; k += base) {
-
-			if (index >= inputLength) {
-				error('invalid-input');
-			}
-
-			const digit = basicToDigit(input.charCodeAt(index++));
-
-			if (digit >= base || digit > floor((maxInt - i) / w)) {
-				error('overflow');
-			}
-
-			i += digit * w;
-			const t = k <= bias ? tMin : (k >= bias + tMax ? tMax : k - bias);
-
-			if (digit < t) {
-				break;
-			}
-
-			const baseMinusT = base - t;
-			if (w > floor(maxInt / baseMinusT)) {
-				error('overflow');
-			}
-
-			w *= baseMinusT;
-
-		}
-
-		const out = output.length + 1;
-		bias = adapt(i - oldi, out, oldi == 0);
-
-		// `i` was supposed to wrap around from `out` to `0`,
-		// incrementing `n` each time, so we'll fix that now:
-		if (floor(i / out) > maxInt - n) {
-			error('overflow');
-		}
-
-		n += floor(i / out);
-		i %= out;
-
-		// Insert `n` at position `i` of the output.
-		output.splice(i++, 0, n);
-
-	}
-
-	return String.fromCodePoint(...output);
-};
-
-/**
- * Converts a string of Unicode symbols (e.g. a domain name label) to a
- * Punycode string of ASCII-only symbols.
- * @memberOf punycode
- * @param {String} input The string of Unicode symbols.
- * @returns {String} The resulting Punycode string of ASCII-only symbols.
- */
-const encode = function(input) {
-	const output = [];
-
-	// Convert the input in UCS-2 to an array of Unicode code points.
-	input = ucs2decode(input);
-
-	// Cache the length.
-	let inputLength = input.length;
-
-	// Initialize the state.
-	let n = initialN;
-	let delta = 0;
-	let bias = initialBias;
-
-	// Handle the basic code points.
-	for (const currentValue of input) {
-		if (currentValue < 0x80) {
-			output.push(stringFromCharCode(currentValue));
-		}
-	}
-
-	let basicLength = output.length;
-	let handledCPCount = basicLength;
-
-	// `handledCPCount` is the number of code points that have been handled;
-	// `basicLength` is the number of basic code points.
-
-	// Finish the basic string with a delimiter unless it's empty.
-	if (basicLength) {
-		output.push(delimiter);
-	}
-
-	// Main encoding loop:
-	while (handledCPCount < inputLength) {
-
-		// All non-basic code points < n have been handled already. Find the next
-		// larger one:
-		let m = maxInt;
-		for (const currentValue of input) {
-			if (currentValue >= n && currentValue < m) {
-				m = currentValue;
-			}
-		}
-
-		// Increase `delta` enough to advance the decoder's <n,i> state to <m,0>,
-		// but guard against overflow.
-		const handledCPCountPlusOne = handledCPCount + 1;
-		if (m - n > floor((maxInt - delta) / handledCPCountPlusOne)) {
-			error('overflow');
-		}
-
-		delta += (m - n) * handledCPCountPlusOne;
-		n = m;
-
-		for (const currentValue of input) {
-			if (currentValue < n && ++delta > maxInt) {
-				error('overflow');
-			}
-			if (currentValue == n) {
-				// Represent delta as a generalized variable-length integer.
-				let q = delta;
-				for (let k = base; /* no condition */; k += base) {
-					const t = k <= bias ? tMin : (k >= bias + tMax ? tMax : k - bias);
-					if (q < t) {
-						break;
-					}
-					const qMinusT = q - t;
-					const baseMinusT = base - t;
-					output.push(
-						stringFromCharCode(digitToBasic(t + qMinusT % baseMinusT, 0))
-					);
-					q = floor(qMinusT / baseMinusT);
-				}
-
-				output.push(stringFromCharCode(digitToBasic(q, 0)));
-				bias = adapt(delta, handledCPCountPlusOne, handledCPCount == basicLength);
-				delta = 0;
-				++handledCPCount;
-			}
-		}
-
-		++delta;
-		++n;
-
-	}
-	return output.join('');
-};
-
-/**
- * Converts a Punycode string representing a domain name or an email address
- * to Unicode. Only the Punycoded parts of the input will be converted, i.e.
- * it doesn't matter if you call it on a string that has already been
- * converted to Unicode.
- * @memberOf punycode
- * @param {String} input The Punycoded domain name or email address to
- * convert to Unicode.
- * @returns {String} The Unicode representation of the given Punycode
- * string.
- */
-const toUnicode = function(input) {
-	return mapDomain(input, function(string) {
-		return regexPunycode.test(string)
-			? decode(string.slice(4).toLowerCase())
-			: string;
-	});
-};
-
-/**
- * Converts a Unicode string representing a domain name or an email address to
- * Punycode. Only the non-ASCII parts of the domain name will be converted,
- * i.e. it doesn't matter if you call it with a domain that's already in
- * ASCII.
- * @memberOf punycode
- * @param {String} input The domain name or email address to convert, as a
- * Unicode string.
- * @returns {String} The Punycode representation of the given domain name or
- * email address.
- */
-const toASCII = function(input) {
-	return mapDomain(input, function(string) {
-		return regexNonASCII.test(string)
-			? 'xn--' + encode(string)
-			: string;
-	});
-};
-
-/*--------------------------------------------------------------------------*/
-
-/** Define the public API */
-const punycode = {
-	/**
-	 * A string representing the current Punycode.js version number.
-	 * @memberOf punycode
-	 * @type String
-	 */
-	'version': '2.0.0',
-	/**
-	 * An object of methods to convert from JavaScript's internal character
-	 * representation (UCS-2) to Unicode code points, and back.
-	 * @see <https://mathiasbynens.be/notes/javascript-encoding>
-	 * @memberOf punycode
-	 * @type Object
-	 */
-	'ucs2': {
-		'decode': ucs2decode,
-		'encode': ucs2encode
-	},
-	'decode': decode,
-	'encode': encode,
-	'toASCII': toASCII,
-	'toUnicode': toUnicode
-};
-
-module.exports = punycode;
diff --git a/lib/url.js b/lib/url.js
index 94fecc94270431..d7bf36900bc367 100644
--- a/lib/url.js
+++ b/lib/url.js
@@ -4,7 +4,7 @@ function importPunycode() {
   try {
     return process.binding('icu');
   } catch (e) {
-    return require('punycode');
+    return require('internal/punycode');
   }
 }
 
diff --git a/node.gyp b/node.gyp
index e8b957267e9710..75c63e85b6d9f7 100644
--- a/node.gyp
+++ b/node.gyp
@@ -84,6 +84,7 @@
       'lib/internal/process/stdio.js',
       'lib/internal/process/warning.js',
       'lib/internal/process.js',
+      'lib/internal/punycode.js',
       'lib/internal/readline.js',
       'lib/internal/repl.js',
       'lib/internal/socket_list.js',
diff --git a/test/message/core_line_numbers.out b/test/message/core_line_numbers.out
index 0dd38a3996d8e9..40cdf764447ef3 100644
--- a/test/message/core_line_numbers.out
+++ b/test/message/core_line_numbers.out
@@ -1,10 +1,10 @@
-punycode.js:42
+internal/punycode.js:42
 	throw new RangeError(errors[type]);
 	^
 
 RangeError: Invalid input
-    at error (punycode.js:42:*)
-    at Object.decode (punycode.js:*:*)
+    at error (internal/punycode.js:42:*)
+    at Object.decode (internal/punycode.js:*:*)
     at Object.<anonymous> (*test*message*core_line_numbers.js:*:*)
     at Module._compile (module.js:*:*)
     at Object.Module._extensions..js (module.js:*:*)