diff --git a/Libraries/LibJS/AST.h b/Libraries/LibJS/AST.h
index 8d87033230f..824c0c28031 100644
--- a/Libraries/LibJS/AST.h
+++ b/Libraries/LibJS/AST.h
@@ -1340,7 +1340,7 @@ private:
 
 class RegExpLiteral final : public Expression {
 public:
-    RegExpLiteral(SourceRange source_range, regex::Parser::Result parsed_regex, String parsed_pattern, regex::RegexOptions<ECMAScriptFlags> parsed_flags, String pattern, String flags)
+    RegExpLiteral(SourceRange source_range, regex::Parser::Result parsed_regex, String parsed_pattern, regex::RegexOptions<ECMAScriptFlags> parsed_flags, Utf16String pattern, Utf16String flags)
         : Expression(move(source_range))
         , m_parsed_regex(move(parsed_regex))
         , m_parsed_pattern(move(parsed_pattern))
@@ -1356,15 +1356,15 @@ public:
     regex::Parser::Result const& parsed_regex() const { return m_parsed_regex; }
     String const& parsed_pattern() const { return m_parsed_pattern; }
     regex::RegexOptions<ECMAScriptFlags> const& parsed_flags() const { return m_parsed_flags; }
-    String const& pattern() const { return m_pattern; }
-    String const& flags() const { return m_flags; }
+    Utf16String const& pattern() const { return m_pattern; }
+    Utf16String const& flags() const { return m_flags; }
 
 private:
     regex::Parser::Result m_parsed_regex;
     String m_parsed_pattern;
     regex::RegexOptions<ECMAScriptFlags> m_parsed_flags;
-    String m_pattern;
-    String m_flags;
+    Utf16String m_pattern;
+    Utf16String m_flags;
 };
 
 class PrivateIdentifier final : public Expression {
diff --git a/Libraries/LibJS/Bytecode/ASTCodegen.cpp b/Libraries/LibJS/Bytecode/ASTCodegen.cpp
index 2366ed923ac..baae42a262d 100644
--- a/Libraries/LibJS/Bytecode/ASTCodegen.cpp
+++ b/Libraries/LibJS/Bytecode/ASTCodegen.cpp
@@ -444,8 +444,8 @@ Bytecode::CodeGenerationErrorOr<Optional<ScopedOperand>> StringLiteral::generate
 Bytecode::CodeGenerationErrorOr<Optional<ScopedOperand>> RegExpLiteral::generate_bytecode(Bytecode::Generator& generator, Optional<ScopedOperand> preferred_dst) const
 {
     Bytecode::Generator::SourceLocationScope scope(generator, *this);
-    auto source_index = generator.intern_string(m_pattern);
-    auto flags_index = generator.intern_string(m_flags);
+    auto source_index = generator.intern_string(m_pattern.to_utf8_but_should_be_ported_to_utf16());
+    auto flags_index = generator.intern_string(m_flags.to_utf8_but_should_be_ported_to_utf16());
     auto regex_index = generator.intern_regex(Bytecode::ParsedRegex {
         .regex = m_parsed_regex,
         .pattern = m_parsed_pattern,
diff --git a/Libraries/LibJS/Bytecode/Interpreter.cpp b/Libraries/LibJS/Bytecode/Interpreter.cpp
index c784cecac74..90ba480f392 100644
--- a/Libraries/LibJS/Bytecode/Interpreter.cpp
+++ b/Libraries/LibJS/Bytecode/Interpreter.cpp
@@ -1542,7 +1542,7 @@ inline ThrowCompletionOr<CalleeAndThis> get_callee_and_this_from_environment(Byt
 }
 
 // 13.2.7.3 Runtime Semantics: Evaluation, https://tc39.es/ecma262/#sec-regular-expression-literals-runtime-semantics-evaluation
-inline Value new_regexp(VM& vm, ParsedRegex const& parsed_regex, String const& pattern, String const& flags)
+inline Value new_regexp(VM& vm, ParsedRegex const& parsed_regex, Utf16String pattern, Utf16String flags)
 {
     // 1. Let pattern be CodePointsToString(BodyText of RegularExpressionLiteral).
     // 2. Let flags be CodePointsToString(FlagText of RegularExpressionLiteral).
@@ -1551,7 +1551,7 @@ inline Value new_regexp(VM& vm, ParsedRegex const& parsed_regex, String const& p
     auto& realm = *vm.current_realm();
     Regex<ECMA262> regex(parsed_regex.regex, parsed_regex.pattern.to_byte_string(), parsed_regex.flags);
     // NOTE: We bypass RegExpCreate and subsequently RegExpAlloc as an optimization to use the already parsed values.
-    auto regexp_object = RegExpObject::create(realm, move(regex), pattern, flags);
+    auto regexp_object = RegExpObject::create(realm, move(regex), move(pattern), move(flags));
     // RegExpAlloc has these two steps from the 'Legacy RegExp features' proposal.
     regexp_object->set_realm(realm);
     // We don't need to check 'If SameValue(newTarget, thisRealm.[[Intrinsics]].[[%RegExp%]]) is true'
@@ -2264,8 +2264,8 @@ void NewRegExp::execute_impl(Bytecode::Interpreter& interpreter) const
         new_regexp(
             interpreter.vm(),
             interpreter.current_executable().regex_table->get(m_regex_index),
-            interpreter.current_executable().get_string(m_source_index),
-            interpreter.current_executable().get_string(m_flags_index)));
+            Utf16String::from_utf8(interpreter.current_executable().get_string(m_source_index)),
+            Utf16String::from_utf8(interpreter.current_executable().get_string(m_flags_index))));
 }
 
 #define JS_DEFINE_NEW_BUILTIN_ERROR_OP(ErrorName)                                                                      \
diff --git a/Libraries/LibJS/Parser.cpp b/Libraries/LibJS/Parser.cpp
index 5699d14153b..e2fd95006f2 100644
--- a/Libraries/LibJS/Parser.cpp
+++ b/Libraries/LibJS/Parser.cpp
@@ -1858,16 +1858,17 @@ Parser::PrimaryExpressionParseResult Parser::parse_primary_expression()
 NonnullRefPtr<RegExpLiteral const> Parser::parse_regexp_literal()
 {
     auto rule_start = push_start();
-    auto pattern = consume().value().to_utf8_but_should_be_ported_to_utf16();
-    // Remove leading and trailing slash.
-    pattern = MUST(pattern.substring_from_byte_offset(1, pattern.bytes().size() - 2));
+    auto pattern_view = consume().value();
 
-    auto flags = String {};
+    // Remove leading and trailing slash.
+    auto pattern = Utf16String::from_utf16(pattern_view.substring_view(1, pattern_view.length_in_code_units() - 2));
+
+    Utf16String flags {};
     auto parsed_flags = RegExpObject::default_flags;
 
     if (match(TokenType::RegexFlags)) {
         auto flags_start = position();
-        flags = consume().value().to_utf8_but_should_be_ported_to_utf16();
+        flags = consume().fly_string_value().to_utf16_string();
 
         auto parsed_flags_or_error = regex_flags_from_string(flags);
         if (parsed_flags_or_error.is_error())
@@ -1890,7 +1891,7 @@ NonnullRefPtr<RegExpLiteral const> Parser::parse_regexp_literal()
         syntax_error(MUST(String::formatted("RegExp compile error: {}", Regex<ECMA262>(parsed_regex, parsed_pattern.to_byte_string(), parsed_flags).error_string())), rule_start.position());
 
     SourceRange range { m_source_code, rule_start.position(), position() };
-    return create_ast_node<RegExpLiteral>(move(range), move(parsed_regex), move(parsed_pattern), move(parsed_flags), move(pattern), move(flags));
+    return create_ast_node<RegExpLiteral>(move(range), move(parsed_regex), move(parsed_pattern), parsed_flags, move(pattern), move(flags));
 }
 
 static bool is_simple_assignment_target(Expression const& expression, bool allow_web_reality_call_expression = true)
diff --git a/Libraries/LibJS/Runtime/RegExpObject.cpp b/Libraries/LibJS/Runtime/RegExpObject.cpp
index 57caf5bfc39..33745f3aca7 100644
--- a/Libraries/LibJS/Runtime/RegExpObject.cpp
+++ b/Libraries/LibJS/Runtime/RegExpObject.cpp
@@ -19,12 +19,14 @@ namespace JS {
 
 GC_DEFINE_ALLOCATOR(RegExpObject);
 
-Result<regex::RegexOptions<ECMAScriptFlags>, String> regex_flags_from_string(StringView flags)
+Result<regex::RegexOptions<ECMAScriptFlags>, String> regex_flags_from_string(Utf16View const& flags)
 {
     bool d = false, g = false, i = false, m = false, s = false, u = false, y = false, v = false;
     auto options = RegExpObject::default_flags;
 
-    for (auto ch : flags) {
+    for (size_t index = 0; index < flags.length_in_code_units(); ++index) {
+        auto ch = flags.code_unit_at(index);
+
         switch (ch) {
         case 'd':
             if (d)
@@ -88,18 +90,17 @@ Result<regex::RegexOptions<ECMAScriptFlags>, String> regex_flags_from_string(Str
 }
 
 // 22.2.3.4 Static Semantics: ParsePattern ( patternText, u, v ), https://tc39.es/ecma262/#sec-parsepattern
-ErrorOr<String, ParseRegexPatternError> parse_regex_pattern(StringView pattern, bool unicode, bool unicode_sets)
+ErrorOr<String, ParseRegexPatternError> parse_regex_pattern(Utf16View const& pattern, bool unicode, bool unicode_sets)
 {
     if (unicode && unicode_sets)
         return ParseRegexPatternError { MUST(String::formatted(ErrorType::RegExpObjectIncompatibleFlags.message(), 'u', 'v')) };
 
-    auto utf16_pattern = Utf16String::from_utf8(pattern);
     StringBuilder builder;
 
     // FIXME: We need to escape multi-byte code units for LibRegex to parse since the lexer there doesn't handle unicode.
     auto previous_code_unit_was_backslash = false;
-    for (size_t i = 0; i < utf16_pattern.length_in_code_units(); ++i) {
-        u16 code_unit = utf16_pattern.code_unit_at(i);
+    for (size_t i = 0; i < pattern.length_in_code_units(); ++i) {
+        u16 code_unit = pattern.code_unit_at(i);
 
         if (code_unit > 0x7f) {
             // Incorrectly escaping this code unit will result in a wildly different regex than intended
@@ -123,7 +124,7 @@ ErrorOr<String, ParseRegexPatternError> parse_regex_pattern(StringView pattern,
 }
 
 // 22.2.3.4 Static Semantics: ParsePattern ( patternText, u, v ), https://tc39.es/ecma262/#sec-parsepattern
-ThrowCompletionOr<String> parse_regex_pattern(VM& vm, StringView pattern, bool unicode, bool unicode_sets)
+ThrowCompletionOr<String> parse_regex_pattern(VM& vm, Utf16View const& pattern, bool unicode, bool unicode_sets)
 {
     auto result = parse_regex_pattern(pattern, unicode, unicode_sets);
     if (result.is_error())
@@ -137,7 +138,7 @@ GC::Ref<RegExpObject> RegExpObject::create(Realm& realm)
     return realm.create<RegExpObject>(realm.intrinsics().regexp_prototype());
 }
 
-GC::Ref<RegExpObject> RegExpObject::create(Realm& realm, Regex<ECMA262> regex, String pattern, String flags)
+GC::Ref<RegExpObject> RegExpObject::create(Realm& realm, Regex<ECMA262> regex, Utf16String pattern, Utf16String flags)
 {
     return realm.create<RegExpObject>(move(regex), move(pattern), move(flags), realm.intrinsics().regexp_prototype());
 }
@@ -147,10 +148,12 @@ RegExpObject::RegExpObject(Object& prototype)
 {
 }
 
-static RegExpObject::Flags to_flag_bits(StringView flags)
+static RegExpObject::Flags to_flag_bits(Utf16View const& flags)
 {
     RegExpObject::Flags flag_bits = static_cast<RegExpObject::Flags>(0);
-    for (auto ch : flags) {
+
+    for (size_t i = 0; i < flags.length_in_code_units(); ++i) {
+        auto ch = flags.code_unit_at(i);
         switch (ch) {
 #define __JS_ENUMERATE(FlagName, flagName, flag_name, flag_char) \
     case #flag_char[0]:                                          \
@@ -165,7 +168,7 @@ static RegExpObject::Flags to_flag_bits(StringView flags)
     return flag_bits;
 }
 
-RegExpObject::RegExpObject(Regex<ECMA262> regex, String pattern, String flags, Object& prototype)
+RegExpObject::RegExpObject(Regex<ECMA262> regex, Utf16String pattern, Utf16String flags, Object& prototype)
     : Object(ConstructWithPrototypeTag::Tag, prototype)
     , m_pattern(move(pattern))
     , m_flags(move(flags))
@@ -189,14 +192,14 @@ ThrowCompletionOr<GC::Ref<RegExpObject>> RegExpObject::regexp_initialize(VM& vm,
     // 1. If pattern is undefined, let P be the empty String.
     // 2. Else, let P be ? ToString(pattern).
     auto pattern = pattern_value.is_undefined()
-        ? String {}
-        : TRY(pattern_value.to_string(vm));
+        ? Utf16String {}
+        : TRY(pattern_value.to_utf16_string(vm));
 
     // 3. If flags is undefined, let F be the empty String.
     // 4. Else, let F be ? ToString(flags).
     auto flags = flags_value.is_undefined()
-        ? String {}
-        : TRY(flags_value.to_string(vm));
+        ? Utf16String {}
+        : TRY(flags_value.to_utf16_string(vm));
 
     // 5. If F contains any code unit other than "d", "g", "i", "m", "s", "u", "v", or "y", or if F contains any code unit more than once, throw a SyntaxError exception.
     // 6. If F contains "i", let i be true; else let i be false.
@@ -271,9 +274,9 @@ String RegExpObject::escape_regexp_pattern() const
 
     // FIXME: Check the 'u' and 'v' flags and escape accordingly
     StringBuilder builder;
-    auto pattern = Utf8View { m_pattern };
     auto escaped = false;
-    for (auto code_point : pattern) {
+
+    for (auto code_point : m_pattern) {
         if (escaped) {
             escaped = false;
             builder.append_code_point('\\');
diff --git a/Libraries/LibJS/Runtime/RegExpObject.h b/Libraries/LibJS/Runtime/RegExpObject.h
index b0958610099..dd24057d08d 100644
--- a/Libraries/LibJS/Runtime/RegExpObject.h
+++ b/Libraries/LibJS/Runtime/RegExpObject.h
@@ -19,12 +19,12 @@ namespace JS {
 JS_API ThrowCompletionOr<GC::Ref<RegExpObject>> regexp_create(VM&, Value pattern, Value flags);
 ThrowCompletionOr<GC::Ref<RegExpObject>> regexp_alloc(VM&, FunctionObject& new_target);
 
-Result<regex::RegexOptions<ECMAScriptFlags>, String> regex_flags_from_string(StringView flags);
+Result<regex::RegexOptions<ECMAScriptFlags>, String> regex_flags_from_string(Utf16View const& flags);
 struct ParseRegexPatternError {
     String error;
 };
-ErrorOr<String, ParseRegexPatternError> parse_regex_pattern(StringView pattern, bool unicode, bool unicode_sets);
-ThrowCompletionOr<String> parse_regex_pattern(VM& vm, StringView pattern, bool unicode, bool unicode_sets);
+ErrorOr<String, ParseRegexPatternError> parse_regex_pattern(Utf16View const& pattern, bool unicode, bool unicode_sets);
+ThrowCompletionOr<String> parse_regex_pattern(VM& vm, Utf16View const& pattern, bool unicode, bool unicode_sets);
 
 class RegExpObject : public Object {
     JS_OBJECT(RegExpObject, Object);
@@ -51,7 +51,7 @@ public:
     };
 
     static GC::Ref<RegExpObject> create(Realm&);
-    static GC::Ref<RegExpObject> create(Realm&, Regex<ECMA262> regex, String pattern, String flags);
+    static GC::Ref<RegExpObject> create(Realm&, Regex<ECMA262> regex, Utf16String pattern, Utf16String flags);
 
     ThrowCompletionOr<GC::Ref<RegExpObject>> regexp_initialize(VM&, Value pattern, Value flags);
     String escape_regexp_pattern() const;
@@ -59,8 +59,8 @@ public:
     virtual void initialize(Realm&) override;
     virtual ~RegExpObject() override = default;
 
-    String const& pattern() const { return m_pattern; }
-    String const& flags() const { return m_flags; }
+    Utf16String const& pattern() const { return m_pattern; }
+    Utf16String const& flags() const { return m_flags; }
     Flags flag_bits() const { return m_flag_bits; }
     Regex<ECMA262> const& regex() { return *m_regex; }
     Regex<ECMA262> const& regex() const { return *m_regex; }
@@ -72,13 +72,13 @@ public:
 
 private:
     RegExpObject(Object& prototype);
-    RegExpObject(Regex<ECMA262> regex, String pattern, String flags, Object& prototype);
+    RegExpObject(Regex<ECMA262> regex, Utf16String pattern, Utf16String flags, Object& prototype);
 
     virtual bool is_regexp_object() const final { return true; }
     virtual void visit_edges(Visitor&) override;
 
-    String m_pattern;
-    String m_flags;
+    Utf16String m_pattern;
+    Utf16String m_flags;
     Flags m_flag_bits { 0 };
     bool m_legacy_features_enabled { false }; // [[LegacyFeaturesEnabled]]
     // Note: This is initialized in RegExpAlloc, but will be non-null afterwards
diff --git a/Libraries/LibJS/Runtime/RegExpPrototype.cpp b/Libraries/LibJS/Runtime/RegExpPrototype.cpp
index e8a82d3e6c9..64c1ffd8af9 100644
--- a/Libraries/LibJS/Runtime/RegExpPrototype.cpp
+++ b/Libraries/LibJS/Runtime/RegExpPrototype.cpp
@@ -187,7 +187,7 @@ static ThrowCompletionOr<Value> regexp_builtin_exec(VM& vm, RegExpObject& regexp
     // 5. If flags contains "y", let sticky be true; else let sticky be false.
     bool sticky = regex.options().has_flag_set(ECMAScriptFlags::Sticky);
     // 6. If flags contains "d", let hasIndices be true, else let hasIndices be false.
-    bool has_indices = regexp_object.flags().bytes_as_string_view().find('d').has_value();
+    bool has_indices = regexp_object.flags().contains('d');
 
     // 7. If global is false and sticky is false, set lastIndex to 0.
     if (!global && !sticky)
diff --git a/Libraries/LibWeb/HTML/StructuredSerialize.cpp b/Libraries/LibWeb/HTML/StructuredSerialize.cpp
index a4889719e50..25a329f5075 100644
--- a/Libraries/LibWeb/HTML/StructuredSerialize.cpp
+++ b/Libraries/LibWeb/HTML/StructuredSerialize.cpp
@@ -605,6 +605,11 @@ public:
             return JS::PrimitiveString::create(m_vm, string);
         };
 
+        auto decode_utf16_string = [&]() {
+            auto string = m_serialized.decode<Utf16String>();
+            return JS::PrimitiveString::create(m_vm, string);
+        };
+
         auto decode_big_int = [&]() {
             auto string = m_serialized.decode<String>();
             return JS::BigInt::create(m_vm, MUST(::Crypto::SignedBigInteger::from_base(10, string)));
@@ -665,8 +670,8 @@ public:
         // 11. Otherwise, if serialized.[[Type]] is "RegExp", then set value to a new RegExp object in targetRealm whose [[RegExpMatcher]] internal slot value is serialized.[[RegExpMatcher]],
         //     whose [[OriginalSource]] internal slot value is serialized.[[OriginalSource]], and whose [[OriginalFlags]] internal slot value is serialized.[[OriginalFlags]].
         case ValueTag::RegExpObject: {
-            auto pattern = decode_string();
-            auto flags = decode_string();
+            auto pattern = decode_utf16_string();
+            auto flags = decode_utf16_string();
 
             value = MUST(JS::regexp_create(m_vm, pattern, flags));
             break;