diff --git a/polyfill/lib/intl.mjs b/polyfill/lib/intl.mjs
index a0ee6899a5..610bcbabec 100644
--- a/polyfill/lib/intl.mjs
+++ b/polyfill/lib/intl.mjs
@@ -2,7 +2,6 @@ import { ES } from './ecmascript.mjs';
 import { GetIntrinsic } from './intrinsicclass.mjs';
 import {
   GetSlot,
-  INSTANT,
   ISO_YEAR,
   ISO_MONTH,
   ISO_DAY,
@@ -12,8 +11,7 @@ import {
   ISO_MILLISECOND,
   ISO_MICROSECOND,
   ISO_NANOSECOND,
-  CALENDAR,
-  TIME_ZONE
+  CALENDAR
 } from './slots.mjs';
 
 const DATE = Symbol('date');
@@ -21,11 +19,9 @@ const YM = Symbol('ym');
 const MD = Symbol('md');
 const TIME = Symbol('time');
 const DATETIME = Symbol('datetime');
-const ZONED = Symbol('zoneddatetime');
 const INST = Symbol('instant');
 const ORIGINAL = Symbol('original');
 const TZ_RESOLVED = Symbol('timezone');
-const TZ_GIVEN = Symbol('timezone-id-given');
 const CAL_ID = Symbol('calendar-id');
 const LOCALE = Symbol('locale');
 const OPTIONS = Symbol('options');
@@ -83,7 +79,6 @@ export function DateTimeFormat(locale = undefined, options = undefined) {
     this[OPTIONS] = options;
   }
 
-  this[TZ_GIVEN] = options.timeZone ? options.timeZone : null;
   this[LOCALE] = ro.locale;
   this[ORIGINAL] = original;
   this[TZ_RESOLVED] = ro.timeZone;
@@ -93,7 +88,6 @@ export function DateTimeFormat(locale = undefined, options = undefined) {
   this[MD] = monthDayAmend;
   this[TIME] = timeAmend;
   this[DATETIME] = datetimeAmend;
-  this[ZONED] = zonedDateTimeAmend;
   this[INST] = instantAmend;
 }
 
@@ -127,26 +121,17 @@ function resolvedOptions() {
   return this[ORIGINAL].resolvedOptions();
 }
 
-function adjustFormatterTimeZone(formatter, timeZone) {
-  if (!timeZone) return formatter;
-  const options = formatter.resolvedOptions();
-  if (options.timeZone === timeZone) return formatter;
-  return new IntlDateTimeFormat(options.locale, { ...options, timeZone });
-}
-
 function format(datetime, ...rest) {
-  let { instant, formatter, timeZone } = extractOverrides(datetime, this);
+  let { instant, formatter } = extractOverrides(datetime, this);
   if (instant && formatter) {
-    formatter = adjustFormatterTimeZone(formatter, timeZone);
     return formatter.format(instant.epochMilliseconds);
   }
   return this[ORIGINAL].format(datetime, ...rest);
 }
 
 function formatToParts(datetime, ...rest) {
-  let { instant, formatter, timeZone } = extractOverrides(datetime, this);
+  let { instant, formatter } = extractOverrides(datetime, this);
   if (instant && formatter) {
-    formatter = adjustFormatterTimeZone(formatter, timeZone);
     return formatter.formatToParts(instant.epochMilliseconds);
   }
   return this[ORIGINAL].formatToParts(datetime, ...rest);
@@ -157,14 +142,10 @@ function formatRange(a, b) {
     if (!sameTemporalType(a, b)) {
       throw new TypeError('Intl.DateTimeFormat.formatRange accepts two values of the same type');
     }
-    const { instant: aa, formatter: aformatter, timeZone: atz } = extractOverrides(a, this);
-    const { instant: bb, formatter: bformatter, timeZone: btz } = extractOverrides(b, this);
-    if (atz && btz && atz !== btz) {
-      throw new RangeError('cannot format range between different time zones');
-    }
+    const { instant: aa, formatter: aformatter } = extractOverrides(a, this);
+    const { instant: bb, formatter: bformatter } = extractOverrides(b, this);
     if (aa && bb && aformatter && bformatter && aformatter === bformatter) {
-      const formatter = adjustFormatterTimeZone(aformatter, atz);
-      return formatter.formatRange(aa.epochMilliseconds, bb.epochMilliseconds);
+      return aformatter.formatRange(aa.epochMilliseconds, bb.epochMilliseconds);
     }
   }
   return this[ORIGINAL].formatRange(a, b);
@@ -175,14 +156,10 @@ function formatRangeToParts(a, b) {
     if (!sameTemporalType(a, b)) {
       throw new TypeError('Intl.DateTimeFormat.formatRangeToParts accepts two values of the same type');
     }
-    const { instant: aa, formatter: aformatter, timeZone: atz } = extractOverrides(a, this);
-    const { instant: bb, formatter: bformatter, timeZone: btz } = extractOverrides(b, this);
-    if (atz && btz && atz !== btz) {
-      throw new RangeError('cannot format range between different time zones');
-    }
+    const { instant: aa, formatter: aformatter } = extractOverrides(a, this);
+    const { instant: bb, formatter: bformatter } = extractOverrides(b, this);
     if (aa && bb && aformatter && bformatter && aformatter === bformatter) {
-      const formatter = adjustFormatterTimeZone(aformatter, atz);
-      return formatter.formatRangeToParts(aa.epochMilliseconds, bb.epochMilliseconds);
+      return aformatter.formatRangeToParts(aa.epochMilliseconds, bb.epochMilliseconds);
     }
   }
   return this[ORIGINAL].formatRangeToParts(a, b);
@@ -298,21 +275,6 @@ function datetimeAmend(options) {
   return options;
 }
 
-function zonedDateTimeAmend(options) {
-  if (!hasTimeOptions(options) && !hasDateOptions(options)) {
-    options = ObjectAssign({}, options, {
-      year: 'numeric',
-      month: 'numeric',
-      day: 'numeric',
-      hour: 'numeric',
-      minute: 'numeric',
-      second: 'numeric'
-    });
-    if (options.timeZoneName === undefined) options.timeZoneName = 'short';
-  }
-  return options;
-}
-
 function instantAmend(options) {
   if (!hasTimeOptions(options) && !hasDateOptions(options)) {
     options = ObjectAssign({}, options, {
@@ -465,24 +427,9 @@ function extractOverrides(temporalObj, main) {
   }
 
   if (ES.IsTemporalZonedDateTime(temporalObj)) {
-    const calendar = ES.ToTemporalCalendarIdentifier(GetSlot(temporalObj, CALENDAR));
-    if (calendar !== 'iso8601' && calendar !== main[CAL_ID]) {
-      throw new RangeError(
-        `cannot format ZonedDateTime with calendar ${calendar} in locale with calendar ${main[CAL_ID]}`
-      );
-    }
-
-    let timeZone = GetSlot(temporalObj, TIME_ZONE);
-    const objTimeZone = ES.ToTemporalTimeZoneIdentifier(timeZone);
-    if (main[TZ_GIVEN] && main[TZ_GIVEN] !== objTimeZone) {
-      throw new RangeError(`timeZone option ${main[TZ_GIVEN]} doesn't match actual time zone ${objTimeZone}`);
-    }
-
-    return {
-      instant: GetSlot(temporalObj, INSTANT),
-      formatter: getPropLazy(main, ZONED),
-      timeZone: objTimeZone
-    };
+    throw new TypeError(
+      'Temporal.ZonedDateTime not supported in DateTimeFormat methods. Use toLocaleString() instead.'
+    );
   }
 
   if (ES.IsTemporalInstant(temporalObj)) {
diff --git a/polyfill/lib/zoneddatetime.mjs b/polyfill/lib/zoneddatetime.mjs
index a665b836cb..41b9d83d23 100644
--- a/polyfill/lib/zoneddatetime.mjs
+++ b/polyfill/lib/zoneddatetime.mjs
@@ -21,6 +21,7 @@ import {
 import bigInt from 'big-integer';
 
 const ArrayPrototypePush = Array.prototype.push;
+const customResolvedOptions = DateTimeFormat.prototype.resolvedOptions;
 const ObjectCreate = Object.create;
 
 export class ZonedDateTime {
@@ -441,7 +442,60 @@ export class ZonedDateTime {
   }
   toLocaleString(locales = undefined, options = undefined) {
     if (!ES.IsTemporalZonedDateTime(this)) throw new TypeError('invalid receiver');
-    return new DateTimeFormat(locales, options).format(this);
+    options = ES.GetOptionsObject(options);
+
+    const optionsCopy = ObjectCreate(null);
+    // This is not quite per specification, but this polyfill's DateTimeFormat
+    // already doesn't match the InitializeDateTimeFormat operation, and the
+    // access order might change anyway;
+    // see https://github.com/tc39/ecma402/issues/747
+    ES.CopyDataProperties(optionsCopy, options, ['timeZone']);
+
+    if (options.timeZone !== undefined) {
+      throw new TypeError('ZonedDateTime toLocaleString does not accept a timeZone option');
+    }
+
+    if (
+      optionsCopy.year === undefined &&
+      optionsCopy.month === undefined &&
+      optionsCopy.day === undefined &&
+      optionsCopy.weekday === undefined &&
+      optionsCopy.dateStyle === undefined &&
+      optionsCopy.hour === undefined &&
+      optionsCopy.minute === undefined &&
+      optionsCopy.second === undefined &&
+      optionsCopy.timeStyle === undefined &&
+      optionsCopy.dayPeriod === undefined &&
+      optionsCopy.timeZoneName === undefined
+    ) {
+      optionsCopy.timeZoneName = 'short';
+      // The rest of the defaults will be filled in by formatting the Instant
+    }
+
+    let timeZone = ES.ToTemporalTimeZoneIdentifier(GetSlot(this, TIME_ZONE));
+    if (ES.IsTimeZoneOffsetString(timeZone)) {
+      // Note: https://github.com/tc39/ecma402/issues/683 will remove this
+      throw new RangeError('toLocaleString does not support offset string time zones');
+    }
+    timeZone = ES.GetCanonicalTimeZoneIdentifier(timeZone);
+    optionsCopy.timeZone = timeZone;
+
+    const formatter = new DateTimeFormat(locales, optionsCopy);
+
+    const localeCalendarIdentifier = ES.Call(customResolvedOptions, formatter, []).calendar;
+    const calendarIdentifier = ES.ToTemporalCalendarIdentifier(GetSlot(this, CALENDAR));
+    if (
+      calendarIdentifier !== 'iso8601' &&
+      localeCalendarIdentifier !== 'iso8601' &&
+      localeCalendarIdentifier !== calendarIdentifier
+    ) {
+      throw new RangeError(
+        `cannot format ZonedDateTime with calendar ${calendarIdentifier}` +
+          ` in locale with calendar ${localeCalendarIdentifier}`
+      );
+    }
+
+    return formatter.format(GetSlot(this, INSTANT));
   }
   toJSON() {
     if (!ES.IsTemporalZonedDateTime(this)) throw new TypeError('invalid receiver');
diff --git a/spec/intl.html b/spec/intl.html
index 4e4952ef38..6d05e957b9 100644
--- a/spec/intl.html
+++ b/spec/intl.html
@@ -189,10 +189,13 @@ <h1>
     <h1><a href="https://tc39.es/ecma402/#sec-datetimeformat-abstracts">Abstract Operations For DateTimeFormat Objects</a></h1>
 
     <emu-clause id="sec-temporal-initializedatetimeformat" aoid="InitializeDateTimeFormat">
-      <h1>InitializeDateTimeFormat ( _dateTimeFormat_, _locales_, _options_ )</h1>
+      <h1>InitializeDateTimeFormat ( _dateTimeFormat_, _locales_, _options_ [ , <ins>_toLocaleStringTimeZone_</ins> ] )</h1>
 
       <p>
-        The abstract operation InitializeDateTimeFormat accepts the arguments _dateTimeFormat_ (which must be an object), _locales_, and _options_. It initializes _dateTimeFormat_ as a DateTimeFormat object. This abstract operation functions as follows:
+        The abstract operation InitializeDateTimeFormat accepts the arguments _dateTimeFormat_ (which must be an object), _locales_, and _options_.
+        It initializes _dateTimeFormat_ as a DateTimeFormat object.
+        <ins>If an additional _toLocaleStringTimeZone_ argument is provided (which, if present, must be a canonical time zone name string), the time zone will be overridden and some adjustments will be made to the defaults in order to implement the behaviour of `Temporal.ZonedDateTime.prototype.toLocaleString`.</ins>
+        This abstract operation functions as follows:
       </p>
 
       <p>
@@ -238,8 +241,12 @@ <h1>InitializeDateTimeFormat ( _dateTimeFormat_, _locales_, _options_ )</h1>
         1. <del>Set _dateTimeFormat_.[[HourCycle]] to _hc_.</del>
         1. Let _timeZone_ be ? Get(_options_, *"timeZone"*).
         1. If _timeZone_ is *undefined*, then
-          1. Set _timeZone_ to DefaultTimeZone().
+          1. <ins>If _toLocaleStringTimeZone_ is present, then</ins>
+            1. <ins>Set _timeZone_ to _toLocaleStringTimeZone_.</ins>
+          1. <ins>Else,</ins>
+            1. Set _timeZone_ to DefaultTimeZone().
         1. Else,
+          1. <ins>If _toLocaleStringTimeZone_ is present, throw a *TypeError* exception.</ins>
           1. Set _timeZone_ to ? ToString(_timeZone_).
           1. If <del>the result of IsValidTimeZoneName(_timeZone_)</del><ins>IsAvailableTimeZoneName(_timeZone_)</ins> is *false*, then
             1. Throw a *RangeError* exception.
@@ -308,8 +315,9 @@ <h1>InitializeDateTimeFormat ( _dateTimeFormat_, _locales_, _options_ )</h1>
               1. <ins>Set _limitedOptions_.[[&lt;_field_&gt;]] to _formatOptions_.[[&lt;_field_&gt;]].</ins>
           1. <ins>If _needDefaults_ is *true*, then</ins>
             1. <ins>Let _defaultFields_ be the list of fields in the Default fields column of the row.</ins>
+            1. <ins>If the Pattern column of the row is [[TemporalInstantPattern]], and _toLocaleStringTimeZone_ is present, append [[timeZoneName]] to _defaultFields_.</ins>
             1. <ins>For each element _field_ of _defaultFields_, do</ins>
-              1. <ins>If _field_ is *"timeZoneName"*, then</ins>
+              1. <ins>If _field_ is [[timeZoneName]], then</ins>
                 1. <ins>Let _defaultValue_ be *"short"*.</ins>
               1. <ins>Else,</ins>
                 1. <ins>Let _defaultValue_ be *"numeric"*.</ins>
@@ -360,13 +368,8 @@ <h1>InitializeDateTimeFormat ( _dateTimeFormat_, _locales_, _options_ )</h1>
             </tr>
             <tr>
               <th>[[TemporalInstantPattern]]</th>
-              <td>[[weekday]], [[era]], [[year]], [[month]], [[day]], [[hour]], [[minute]], [[second]], [[dayPeriod]], [[fractionalSecondDigits]]</td>
-              <td>[[year]], [[month]], [[day]], [[hour]], [[minute]], [[second]]</td>
-            </tr>
-            <tr>
-              <th>[[TemporalZonedDateTimePattern]]</th>
               <td>[[weekday]], [[era]], [[year]], [[month]], [[day]], [[hour]], [[minute]], [[second]], [[dayPeriod]], [[fractionalSecondDigits]], [[timeZoneName]]</td>
-              <td>[[year]], [[month]], [[day]], [[hour]], [[minute]], [[second]], [[timeZoneName]]</td>
+              <td>[[year]], [[month]], [[day]], [[hour]], [[minute]], [[second]]</td>
             </tr>
           </tbody>
         </table>
@@ -889,33 +892,6 @@ <h1>HandleDateTimeTemporalInstant ( _dateTimeFormat_, _instant_ )</h1>
       </emu-alg>
     </emu-clause>
     </ins>
-    <ins class="block">
-    <emu-clause id="sec-temporal-handledatetimevaluetemporalzoneddatetime" aoid="HandleDateTimeTemporalZonedDateTime">
-      <h1>HandleDateTimeTemporalZonedDateTime ( _dateTimeFormat_, _zonedDateTime_ )</h1>
-
-      <p>
-        The abstract operation HandleDateTimeTemporalZonedDateTime accepts the arguments _dateTimeFormat_ (which must be an object initialized as a DateTimeFormat) and _zonedDateTime_ (which must be an ECMAScript value has an [[InitializedTemporalDateTime]] internal slot). It returns a record which contains the appropriate pattern and epochNanoseconds values for the input. This abstract operation functions as follows:
-      </p>
-
-      <emu-alg>
-      1. Assert: _zonedDateTime_ has an [[InitializedTemporalZonedDateTime]] internal slot.
-      1. Let _pattern_ be _dateTimeFormat_.[[TemporalZonedDateTimePattern]].
-      1. Let _calendar_ be ? ToTemporalCalendarIdentifier(_zonedDateTime_.[[Calendar]]).
-      1. If _calendar_ is not *"iso8601"* and not equal to _dateTimeFormat_.[[Calendar]], then
-        1. Throw a *RangeError* exception.
-      1. Let _timeZone_ be ? ToTemporalTimeZoneIdentifier(_zonedDateTime_.[[TimeZone]]).
-      1. If _dateTimeFormat_.[[TimeZone]] is not equal to DefaultTimeZone(), and _timeZone_ is not equal to _dateTimeFormat_.[[TimeZone]], then
-        1. Throw a *RangeError* exception.
-      1. Let _instant_ be ! CreateTemporalInstant(_zonedDateTime_.[[Nanoseconds]]).
-      1. If _pattern_ is *null*, throw a *TypeError* exception.
-      1. Return the Record {
-          [[pattern]]: _pattern_.[[pattern]],
-          [[rangePatterns]]: _pattern_.[[rangePatterns]],
-          [[epochNanoseconds]]: _instant_.[[Nanoseconds]]
-        }.
-      </emu-alg>
-    </emu-clause>
-    </ins>
 
     <ins class="block">
     <emu-clause id="sec-temporal-handledatetimeothers" aoid="HandleDateTimeOthers">
@@ -967,7 +943,7 @@ <h1>HandleDateTimeValue ( _dateTimeFormat_, _x_ )</h1>
         1. If _x_ has an [[InitializedTemporalInstant]] internal slot, then
           1. Return ? HandleDateTimeTemporalInstant(_dateTimeFormat_, _x_).
         1. Assert: _x_ has an [[InitializedTemporalZonedDateTime]] internal slot.
-        1. Return ? HandleDateTimeTemporalZonedDateTime(_dateTimeFormat_, _x_).
+        1. Throw a *TypeError* exception.
       1. Return ? HandleDateTimeOthers(_dateTimeFormat_, _x_).
       </emu-alg>
     </emu-clause>
@@ -1333,7 +1309,7 @@ <h1><a href="https://tc39.es/ecma402/#sec-properties-of-intl-datetimeformat-inst
       <li>[[DateStyle]], [[TimeStyle]] are each either *undefined*, or a String value with values *"full"*, *"long"*, *"medium"*, or *"short"*.</li>
       <li>[[Pattern]] is a String value as described in <emu-xref href="#sec-intl.datetimeformat-internal-slots"></emu-xref>.</li>
       <li>[[RangePatterns]] is a Record as described in <emu-xref href="#sec-intl.datetimeformat-internal-slots"></emu-xref>.</li>
-      <li><ins>[[TemporalPlainDatePattern]], [[TemporalPlainYearMonthPattern]], [[TemporalPlainMonthDayPattern]], [[TemporalPlainTimePattern]], [[TemporalPlainDateTimePattern]], [[TemporalInstantPattern]], and [[TemporalZonedDateTimePattern]] are records containing at least a [[pattern]] field as described in <emu-xref href="#sec-intl.datetimeformat-internal-slots"></emu-xref>.</ins></li>
+      <li><ins>[[TemporalPlainDatePattern]], [[TemporalPlainYearMonthPattern]], [[TemporalPlainMonthDayPattern]], [[TemporalPlainTimePattern]], [[TemporalPlainDateTimePattern]], and [[TemporalInstantPattern]] are records containing at least a [[pattern]] field as described in <emu-xref href="#sec-intl.datetimeformat-internal-slots"></emu-xref>.</ins></li>
     </ul>
 
     <p>
@@ -2489,8 +2465,17 @@ <h1>Temporal.ZonedDateTime.prototype.toLocaleString ( [ _locales_ [ , _options_
           <emu-alg>
             1. Let _zonedDateTime_ be the *this* value.
             1. Perform ? RequireInternalSlot(_zonedDateTime_, [[InitializedTemporalZonedDateTime]]).
-            1. Let _dateFormat_ be ? Construct(%DateTimeFormat%, « _locales_, _options_ »).
-            1. Return ? FormatDateTime(_dateFormat_, _zonedDateTime_).
+            1. Let _dateTimeFormat_ be ! OrdinaryCreateFromConstructor(%DateTimeFormat%, %DateTimeFormat.protoytpe%, « [[InitializedDateTimeFormat]], [[Locale]], [[Calendar]], [[NumberingSystem]], [[TimeZone]], [[Weekday]], [[Era]], [[Year]], [[Month]], [[Day]], [[DayPeriod]], [[Hour]], [[Minute]], [[Second]], [[FractionalSecondDigits]], [[TimeZoneName]], [[HourCycle]], [[Pattern]], [[BoundFormat]] »).
+            1. Let _timeZone_ be ? ToTemporalTimeZoneIdentifier(_zonedDateTime_.[[TimeZone]]).
+            1. If IsTimeZoneOffsetString(_timeZone_) is *true*, throw a *RangeError* exception.
+            1. If IsAvailableTimeZoneName(_timeZone_) is *false*, throw a *RangeError* exception.
+            1. Set _timeZone_ to CanonicalizeTimeZoneName(_timeZone_).
+            1. Perform ? InitializeDateTimeFormat(_dateTimeFormat_, _locales_, _options_, _timeZone_).
+            1. Let _calendar_ be ? ToTemporalCalendarIdentifier(_zonedDateTime_.[[Calendar]]).
+            1. If _calendar_ is not *"iso8601"* and not equal to _dateTimeFormat_.[[Calendar]], then
+              1. Throw a *RangeError* exception.
+            1. Let _instant_ be ! CreateTemporalInstant(_zonedDateTime_.[[Nanoseconds]]).
+            1. Return ? FormatDateTime(_dateTimeFormat_, _instant_).
           </emu-alg>
         </emu-clause>