diff --git a/lib/serialize/setsMaps.js b/lib/serialize/setsMaps.js
index 28fb4f14..bb814a17 100644
--- a/lib/serialize/setsMaps.js
+++ b/lib/serialize/setsMaps.js
@@ -11,6 +11,7 @@ const t = require('@babel/types');
 // Imports
 const {createDependency, createAssignment} = require('./records.js'),
 	{weakSets, weakMaps} = require('../shared/internal.js'),
+	{SET_TYPE, WEAK_SET_TYPE, registerSerializer} = require('./types.js'),
 	{recordIsCircular} = require('./utils.js');
 
 // Exports
@@ -19,11 +20,24 @@ const setValues = Set.prototype.values,
 	mapEntries = Map.prototype.entries;
 
 module.exports = {
-	serializeSet(set, record) {
-		return this.serializeSetLike(set, [...setValues.call(set)], Set, record);
+	/**
+	 * Trace Set.
+	 * @param {Set} set - Set object
+	 * @param {Object} record - Record
+	 * @returns {number} - Type ID
+	 */
+	traceSet(set, record) {
+		traceSetLike.call(this, set, [...setValues.call(set)], record);
+		return SET_TYPE;
 	},
 
-	serializeWeakSet(set, record) {
+	/**
+	 * Trace WeakSet.
+	 * @param {Set} set - Set object
+	 * @param {Object} record - Record
+	 * @returns {number} - Type ID
+	 */
+	traceWeakSet(set, record) {
 		const {refs} = weakSets.get(set);
 		const entries = [];
 		for (const ref of refs) {
@@ -31,37 +45,8 @@ module.exports = {
 			if (value) entries.push(value);
 		}
 
-		return this.serializeSetLike(set, entries, WeakSet, record);
-	},
-
-	serializeSetLike(set, entries, ctor, record) {
-		const {varNode} = record,
-			varName = varNode.name;
-		let isCircular = false;
-		const entryNodes = [];
-		entries.forEach((val, index) => {
-			const valRecord = this.serializeValue(val, `${varName}_${index}`, `<Set value ${index}>`);
-			if (!isCircular && (recordIsCircular(valRecord))) isCircular = true;
-
-			if (isCircular) {
-				const arr = [valRecord.varNode];
-				const memberNode = t.memberExpression(varNode, t.identifier('add'));
-				const assignmentNode = t.callExpression(memberNode, arr);
-				const assignment = createAssignment(record, assignmentNode, memberNode, 'object');
-				createDependency(assignment, valRecord, arr, 0);
-			} else {
-				entryNodes[index] = valRecord.varNode;
-				createDependency(record, valRecord, entryNodes, index);
-			}
-		});
-
-		const ctorRecord = this.serializeValue(ctor);
-		const node = t.newExpression(
-			ctorRecord.varNode,
-			entryNodes.length > 0 ? [t.arrayExpression(entryNodes)] : []
-		);
-		createDependency(record, ctorRecord, node, 'callee');
-		return this.wrapWithProperties(set, record, node, ctor.prototype);
+		traceSetLike.call(this, set, entries, record);
+		return WEAK_SET_TYPE;
 	},
 
 	serializeMap(map, record) {
@@ -113,3 +98,77 @@ module.exports = {
 		return this.wrapWithProperties(map, record, node, ctor.prototype);
 	}
 };
+
+/**
+ * Trace Set or WeakSet.
+ * @this {Object} Serializer
+ * @param {Set|WeakSet} set - Set/WeakSet object
+ * @param {Array<*>} entries - Set/WeakSet entries
+ * @param {Object} record - Record
+ * @returns {undefined}
+ */
+function traceSetLike(set, entries, record) {
+	const entryRecords = entries.map(
+		(val, index) => this.traceDependency(val, `${record.name}_${index}`, `<Set value ${index}>`, record)
+	);
+	record.extra = {entryRecords};
+	this.traceProperties(set, record, undefined);
+}
+
+/**
+ * Serialize Set.
+ * @this {Object} Serializer
+ * @param {Object} record - Record
+ * @returns {Object} - AST node
+ */
+function serializeSet(record) {
+	return serializeSetLike.call(this, record, Set, this.setPrototypeRecord, true);
+}
+registerSerializer(SET_TYPE, serializeSet);
+
+/**
+ * Serialize WeakSet.
+ * @this {Object} Serializer
+ * @param {Object} record - Record
+ * @returns {Object} - AST node
+ */
+function serializeWeakSet(record) {
+	return serializeSetLike.call(this, record, WeakSet, this.weakSetPrototypeRecord, false);
+}
+registerSerializer(WEAK_SET_TYPE, serializeWeakSet);
+
+/**
+ * Serialize Set or WeakSet.
+ * @this {Object} Serializer
+ * @param {Object} record - Record
+ * @param {Function} ctor - Constructor - `Set` or `WeakSet`
+ * @param {Object} protoRecord - Record for prototype
+ * @param {boolean} isOrdered - `true` if entries are ordered (`true` for Sets, `false` for WeakSets)
+ * @returns {undefined}
+ */
+function serializeSetLike(record, ctor, protoRecord, isOrdered) {
+	const {varNode} = record;
+	let isCircular = false;
+	const entryNodes = [];
+	for (const entryRecord of record.extra.entryRecords) {
+		if (!isOrdered) {
+			isCircular = entryRecord.isCircular;
+		} else if (!isCircular && entryRecord.isCircular) {
+			isCircular = true;
+		}
+
+		const entryNode = this.serializeValue(entryRecord);
+		if (isCircular) {
+			// `set.add(...)`
+			this.assignmentNodes.push(t.expressionStatement(
+				t.callExpression(t.memberExpression(varNode, t.identifier('add')), [entryNode])
+			));
+		} else {
+			entryNodes.push(entryNode);
+		}
+	}
+
+	const ctorNode = this.traceAndSerializeGlobal(ctor),
+		node = t.newExpression(ctorNode, entryNodes.length > 0 ? [t.arrayExpression(entryNodes)] : []);
+	return this.wrapWithProperties(node, record, protoRecord, null);
+}
diff --git a/lib/serialize/trace.js b/lib/serialize/trace.js
index 733b77ad..1553dbd9 100644
--- a/lib/serialize/trace.js
+++ b/lib/serialize/trace.js
@@ -42,6 +42,8 @@ module.exports = {
 		this.arrayPrototypeRecord = this.traceValue(Array.prototype, null, null);
 		this.regexpPrototypeRecord = this.traceValue(RegExp.prototype, null, null);
 		this.datePrototypeRecord = this.traceValue(Date.prototype, null, null);
+		this.setPrototypeRecord = this.traceValue(Set.prototype, null, null);
+		this.weakSetPrototypeRecord = this.traceValue(WeakSet.prototype, null, null);
 		this.urlPrototypeRecord = this.traceValue(URL.prototype, null, null);
 		this.urlSearchParamsPrototypeRecord = this.traceValue(URLSearchParams.prototype, null, null);
 
@@ -144,9 +146,9 @@ module.exports = {
 		if (objType === 'Array') return this.traceArray(val, record);
 		if (objType === 'RegExp') return this.traceRegexp(val, record);
 		if (objType === 'Date') return this.traceDate(val, record);
-		// if (objType === 'Set') return this.traceSet(val, record);
+		if (objType === 'Set') return this.traceSet(val, record);
 		// if (objType === 'Map') return this.traceMap(val, record);
-		// if (objType === 'WeakSet') return this.traceWeakSet(val, record);
+		if (objType === 'WeakSet') return this.traceWeakSet(val, record);
 		// if (objType === 'WeakMap') return this.traceWeakMap(val, record);
 		if (objType === 'WeakRef') return this.traceWeakRef(val, record);
 		if (objType === 'FinalizationRegistry') return this.traceFinalizationRegistry(val, record);
diff --git a/lib/serialize/types.js b/lib/serialize/types.js
index 2746f917..d56e0956 100644
--- a/lib/serialize/types.js
+++ b/lib/serialize/types.js
@@ -12,7 +12,7 @@ const assert = require('simple-invariant');
 
 /* eslint-disable no-bitwise */
 const NO_TYPE = 0,
-	PRIMITIVE_TYPE = 8,
+	PRIMITIVE_TYPE = 16,
 	STRING_TYPE = PRIMITIVE_TYPE | 0,
 	BOOLEAN_TYPE = PRIMITIVE_TYPE | 1,
 	NUMBER_TYPE = PRIMITIVE_TYPE | 2,
@@ -20,15 +20,19 @@ const NO_TYPE = 0,
 	NULL_TYPE = PRIMITIVE_TYPE | 4,
 	UNDEFINED_TYPE = PRIMITIVE_TYPE | 5,
 	NEGATIVE_TYPE = PRIMITIVE_TYPE | 6, // TODO: Should this be a primitive?
-	OBJECT_TYPE = 16,
+	OBJECT_TYPE = 32,
 	ARRAY_TYPE = OBJECT_TYPE | 1,
 	REGEXP_TYPE = OBJECT_TYPE | 2,
 	DATE_TYPE = OBJECT_TYPE | 3,
-	URL_TYPE = OBJECT_TYPE | 4,
-	URL_SEARCH_PARAMS_TYPE = OBJECT_TYPE | 5,
-	FUNCTION_TYPE = 32,
+	SET_TYPE = OBJECT_TYPE | 4,
+	MAP_TYPE = OBJECT_TYPE | 5,
+	WEAK_SET_TYPE = OBJECT_TYPE | 6,
+	WEAK_MAP_TYPE = OBJECT_TYPE | 7,
+	URL_TYPE = OBJECT_TYPE | 8,
+	URL_SEARCH_PARAMS_TYPE = OBJECT_TYPE | 9,
+	FUNCTION_TYPE = 64,
 	METHOD_TYPE = FUNCTION_TYPE | 1,
-	GLOBAL_TYPE = 64,
+	GLOBAL_TYPE = 128,
 	GLOBAL_TOP_LEVEL_TYPE = GLOBAL_TYPE | 0,
 	GLOBAL_MODULE_TYPE = GLOBAL_TYPE | 1,
 	GLOBAL_PROPERTY_TYPE = GLOBAL_TYPE | 2,
@@ -36,7 +40,7 @@ const NO_TYPE = 0,
 	GLOBAL_GETTER_TYPE = GLOBAL_TYPE | 4,
 	GLOBAL_SETTER_TYPE = GLOBAL_TYPE | 5,
 	GLOBAL_MINUS_INFINITY_TYPE = GLOBAL_TYPE | 6,
-	SYMBOL_TYPE = 128,
+	SYMBOL_TYPE = 256,
 	SYMBOL_FOR_TYPE = SYMBOL_TYPE | 1,
 	EXPORT_JS_TYPE = 1,
 	EXPORT_COMMONJS_TYPE = 2,
@@ -60,6 +64,10 @@ module.exports = {
 	ARRAY_TYPE,
 	REGEXP_TYPE,
 	DATE_TYPE,
+	SET_TYPE,
+	MAP_TYPE,
+	WEAK_SET_TYPE,
+	WEAK_MAP_TYPE,
 	URL_TYPE,
 	URL_SEARCH_PARAMS_TYPE,
 	FUNCTION_TYPE,
diff --git a/test/sets.test.js b/test/sets.test.js
index 3077b119..53435f3b 100644
--- a/test/sets.test.js
+++ b/test/sets.test.js
@@ -10,7 +10,7 @@ const {itSerializes, itSerializesEqual} = require('./support/index.js');
 
 // Tests
 
-describe.skip('Sets', () => {
+describe('Sets', () => {
 	itSerializesEqual('no entries', {
 		in: () => new Set(),
 		out: 'new Set',
@@ -89,7 +89,7 @@ describe.skip('Sets', () => {
 		});
 	});
 
-	describe('set subclass', () => {
+	describe.skip('set subclass', () => {
 		itSerializes('no entries', {
 			in() {
 				class S extends Set {}
@@ -187,7 +187,7 @@ describe.skip('Sets', () => {
 	});
 });
 
-describe.skip('WeakSets', () => {
+describe('WeakSets', () => {
 	it('calling `WeakSet()` without `new` throws error', () => {
 		expect(() => WeakSet()).toThrowWithMessage(
 			TypeError, "Class constructor WeakSet cannot be invoked without 'new'"
@@ -234,4 +234,25 @@ describe.skip('WeakSets', () => {
 			expect(weakSet.has(weakSet)).toBeTrue();
 		}
 	});
+
+	itSerializes('with circular contents followed by non-circular', {
+		in() {
+			const weakSet = new WeakSet();
+			weakSet.add(weakSet);
+			const obj = {x: 1};
+			weakSet.add(obj);
+			return {weakSet, obj};
+		},
+		out: `(()=>{
+			const a={x:1},
+				b=new WeakSet([a]);
+			b.add(b);
+			return{weakSet:b,obj:a}
+		})()`,
+		validate({weakSet, obj}) {
+			expect(weakSet).toBeInstanceOf(WeakSet);
+			expect(weakSet.has(weakSet)).toBeTrue();
+			expect(weakSet.has(obj)).toBeTrue();
+		}
+	});
 });