diff --git a/Libraries/LibJS/Runtime/Temporal/ZonedDateTimePrototype.cpp b/Libraries/LibJS/Runtime/Temporal/ZonedDateTimePrototype.cpp
index bbdeeabe4c2..c8a2f92722b 100644
--- a/Libraries/LibJS/Runtime/Temporal/ZonedDateTimePrototype.cpp
+++ b/Libraries/LibJS/Runtime/Temporal/ZonedDateTimePrototype.cpp
@@ -7,6 +7,8 @@
  */
 
 #include <LibJS/Runtime/Date.h>
+#include <LibJS/Runtime/Intl/DateTimeFormat.h>
+#include <LibJS/Runtime/Intl/DateTimeFormatConstructor.h>
 #include <LibJS/Runtime/Temporal/Calendar.h>
 #include <LibJS/Runtime/Temporal/Duration.h>
 #include <LibJS/Runtime/Temporal/Instant.h>
@@ -15,6 +17,7 @@
 #include <LibJS/Runtime/Temporal/PlainTime.h>
 #include <LibJS/Runtime/Temporal/TimeZone.h>
 #include <LibJS/Runtime/Temporal/ZonedDateTimePrototype.h>
+#include <Libraries/LibJS/Runtime/Intl/AbstractOperations.h>
 
 namespace JS::Temporal {
 
@@ -785,15 +788,56 @@ JS_DEFINE_NATIVE_FUNCTION(ZonedDateTimePrototype::to_string)
 }
 
 // 6.3.42 Temporal.ZonedDateTime.prototype.toLocaleString ( [ locales [ , options ] ] ), https://tc39.es/proposal-temporal/#sec-temporal.zoneddatetime.prototype.tolocalestring
-// NOTE: This is the minimum toLocaleString implementation for engines without ECMA-402.
+// 15.12.8.1 Temporal.ZonedDateTime.prototype.toLocaleString ( [ locales [ , options ] ] ), https://tc39.es/proposal-temporal/#sup-properties-of-the-temporal-zoneddatetime-prototype-object
 JS_DEFINE_NATIVE_FUNCTION(ZonedDateTimePrototype::to_locale_string)
 {
+    auto& realm = *vm.current_realm();
+
+    auto locales = vm.argument(0);
+    auto options = vm.argument(1);
+
     // 1. Let zonedDateTime be the this value.
     // 2. Perform ? RequireInternalSlot(zonedDateTime, [[InitializedTemporalZonedDateTime]]).
     auto zoned_date_time = TRY(typed_this_object(vm));
 
-    // 3. Return TemporalZonedDateTimeToString(zonedDateTime, AUTO, AUTO, AUTO, AUTO).
-    return PrimitiveString::create(vm, temporal_zoned_date_time_to_string(zoned_date_time, Auto {}, ShowCalendar::Auto, ShowTimeZoneName::Auto, ShowOffset::Auto));
+    // 3. Let timeZone be zonedDateTime.[[TimeZone]].
+    auto time_zone = zoned_date_time->time_zone();
+
+    // 4. Let timeZoneParseResult be ? ParseTimeZoneIdentifier(timeZone).
+    auto time_zone_parse_result = TRY(parse_time_zone_identifier(vm, time_zone));
+
+    // 5. If timeZoneParseResult.[[OffsetMinutes]] is empty, then
+    if (!time_zone_parse_result.offset_minutes.has_value()) {
+        // a. Let timeZoneIdentifierRecord be GetAvailableNamedTimeZoneIdentifier(timeZone).
+        auto time_zone_identifier_record = Intl::get_available_named_time_zone_identifier(time_zone);
+
+        // b. If timeZoneIdentifierRecord is empty, throw a RangeError exception.
+        if (!time_zone_identifier_record.has_value())
+            return vm.throw_completion<RangeError>(ErrorType::TemporalInvalidTimeZoneName, time_zone);
+
+        // c. Set timeZone to timeZoneIdentifierRecord.[[Identifier]].
+        time_zone = time_zone_identifier_record->identifier;
+    }
+    // 6. Else,
+    else {
+        // a. Set timeZone to FormatOffsetTimeZoneIdentifier(timeZoneParseResult.[[OffsetMinutes]]).
+        time_zone = format_offset_time_zone_identifier(*time_zone_parse_result.offset_minutes);
+    }
+
+    // 7. Let dateTimeFormat be ? CreateDateTimeFormat(%Intl.DateTimeFormat%, locales, options, ANY, ALL, timeZone).
+    auto date_time_format = TRY(Intl::create_date_time_format(vm, realm.intrinsics().intl_date_time_format_constructor(), locales, options, Intl::OptionRequired::Any, Intl::OptionDefaults::All, time_zone));
+
+    // 8. If zonedDateTime.[[Calendar]] is not "iso8601" and CalendarEquals(zonedDateTime.[[Calendar]], dateTimeFormat.[[Calendar]]) is false, then
+    if (zoned_date_time->calendar() != "iso8601"sv && !calendar_equals(zoned_date_time->calendar(), date_time_format->calendar())) {
+        // a. Throw a RangeError exception.
+        return vm.throw_completion<RangeError>(ErrorType::IntlTemporalInvalidCalendar, "Temporal.ZonedDateTime"sv, zoned_date_time->calendar(), date_time_format->calendar());
+    }
+
+    // 9. Let instant be ! CreateTemporalInstant(zonedDateTime.[[EpochNanoseconds]]).
+    auto instant = MUST(create_temporal_instant(vm, zoned_date_time->epoch_nanoseconds()));
+
+    // 10. Return ? FormatDateTime(dateTimeFormat, instant).
+    return PrimitiveString::create(vm, TRY(Intl::format_date_time(vm, date_time_format, instant)));
 }
 
 // 6.3.43 Temporal.ZonedDateTime.prototype.toJSON ( ), https://tc39.es/proposal-temporal/#sec-temporal.zoneddatetime.prototype.tojson
diff --git a/Libraries/LibJS/Tests/builtins/Temporal/ZonedDateTime/ZonedDateTime.prototype.toLocaleString.js b/Libraries/LibJS/Tests/builtins/Temporal/ZonedDateTime/ZonedDateTime.prototype.toLocaleString.js
index cd0d8d1829a..ad13f755f4c 100644
--- a/Libraries/LibJS/Tests/builtins/Temporal/ZonedDateTime/ZonedDateTime.prototype.toLocaleString.js
+++ b/Libraries/LibJS/Tests/builtins/Temporal/ZonedDateTime/ZonedDateTime.prototype.toLocaleString.js
@@ -4,9 +4,20 @@ describe("correct behavior", () => {
     });
 
     test("basic functionality", () => {
-        const plainDateTime = new Temporal.PlainDateTime(2021, 11, 3, 1, 33, 5, 100, 200, 300);
+        const plainDateTime = new Temporal.PlainDateTime(
+            2021,
+            11,
+            3,
+            1,
+            33,
+            5,
+            100,
+            200,
+            300,
+            "gregory"
+        );
         const zonedDateTime = plainDateTime.toZonedDateTime("UTC");
-        expect(zonedDateTime.toLocaleString()).toBe("2021-11-03T01:33:05.1002003+00:00[UTC]");
+        expect(zonedDateTime.toLocaleString()).toBe("11/3/2021, 1:33:5 AM UTC");
     });
 });
 
@@ -16,4 +27,27 @@ describe("errors", () => {
             Temporal.ZonedDateTime.prototype.toLocaleString.call("foo");
         }).toThrowWithMessage(TypeError, "Not an object of type Temporal.ZonedDateTime");
     });
+
+    test("Temporal object must have same calendar", () => {
+        const plainDateTime = new Temporal.PlainDateTime(
+            2021,
+            11,
+            3,
+            1,
+            33,
+            5,
+            100,
+            200,
+            300,
+            "gregory"
+        );
+        const zonedDateTime = plainDateTime.toZonedDateTime("UTC");
+
+        expect(() => {
+            zonedDateTime.toLocaleString("en", { calendar: "iso8601" });
+        }).toThrowWithMessage(
+            RangeError,
+            "Cannot format Temporal.ZonedDateTime with calendar 'gregory' in locale with calendar 'iso8601'"
+        );
+    });
 });