diff --git a/test/intl402/Temporal/PlainDate/prototype/toLocaleString/calendar-mismatch.js b/test/intl402/Temporal/PlainDate/prototype/toLocaleString/calendar-mismatch.js
new file mode 100644
index 0000000000..acf971320b
--- /dev/null
+++ b/test/intl402/Temporal/PlainDate/prototype/toLocaleString/calendar-mismatch.js
@@ -0,0 +1,27 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.prototype.tolocalestring
+description: Calendar must match the locale calendar if not "iso8601"
+features: [Temporal, Intl-enumeration]
+---*/
+
+const localeCalendar = new Intl.DateTimeFormat().resolvedOptions().calendar;
+assert.notSameValue(localeCalendar, "iso8601", "no locale has the ISO calendar");
+
+const sameCalendarInstance = new Temporal.PlainDate(2000, 5, 2, localeCalendar);
+const result = sameCalendarInstance.toLocaleString();
+assert.sameValue(typeof result, "string", "toLocaleString() succeeds when instance has the same calendar as locale");
+
+const isoInstance = new Temporal.PlainDate(2000, 5, 2, "iso8601");
+assert.sameValue(isoInstance.toLocaleString(), result, "toLocaleString() succeeds when instance has the ISO calendar")
+
+// Pick a different calendar that is not ISO and not the locale's calendar
+const calendars = new Set(Intl.supportedValuesOf("calendar"));
+calendars.delete("iso8601");
+calendars.delete(localeCalendar);
+const differentCalendar = calendars.values().next().value;
+
+const differentCalendarInstance = new Temporal.PlainDate(2000, 5, 2, differentCalendar);
+assert.throws(RangeError, () => differentCalendarInstance.toLocaleString(), "calendar mismatch");
diff --git a/test/intl402/Temporal/PlainDateTime/prototype/toLocaleString/calendar-mismatch.js b/test/intl402/Temporal/PlainDateTime/prototype/toLocaleString/calendar-mismatch.js
new file mode 100644
index 0000000000..d57a32bcf3
--- /dev/null
+++ b/test/intl402/Temporal/PlainDateTime/prototype/toLocaleString/calendar-mismatch.js
@@ -0,0 +1,27 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindatetime.prototype.tolocalestring
+description: Calendar must match the locale calendar if not "iso8601"
+features: [Temporal, Intl-enumeration]
+---*/
+
+const localeCalendar = new Intl.DateTimeFormat().resolvedOptions().calendar;
+assert.notSameValue(localeCalendar, "iso8601", "no locale has the ISO calendar");
+
+const sameCalendarInstance = new Temporal.PlainDateTime(2000, 5, 2, 12, 34, 56, 987, 654, 321, localeCalendar);
+const result = sameCalendarInstance.toLocaleString();
+assert.sameValue(typeof result, "string", "toLocaleString() succeeds when instance has the same calendar as locale");
+
+const isoInstance = new Temporal.PlainDateTime(2000, 5, 2, 12, 34, 56, 987, 654, 321, "iso8601");
+assert.sameValue(isoInstance.toLocaleString(), result, "toLocaleString() succeeds when instance has the ISO calendar")
+
+// Pick a different calendar that is not ISO and not the locale's calendar
+const calendars = new Set(Intl.supportedValuesOf("calendar"));
+calendars.delete("iso8601");
+calendars.delete(localeCalendar);
+const differentCalendar = calendars.values().next().value;
+
+const differentCalendarInstance = new Temporal.PlainDateTime(2000, 5, 2, 12, 34, 56, 987, 654, 321, differentCalendar);
+assert.throws(RangeError, () => differentCalendarInstance.toLocaleString(), "calendar mismatch");
diff --git a/test/intl402/Temporal/PlainMonthDay/prototype/toLocaleString/calendar-mismatch.js b/test/intl402/Temporal/PlainMonthDay/prototype/toLocaleString/calendar-mismatch.js
new file mode 100644
index 0000000000..40de8ba551
--- /dev/null
+++ b/test/intl402/Temporal/PlainMonthDay/prototype/toLocaleString/calendar-mismatch.js
@@ -0,0 +1,27 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plainmonthday.prototype.tolocalestring
+description: Calendar must match the locale calendar if not "iso8601"
+features: [Temporal, Intl-enumeration]
+---*/
+
+const localeCalendar = new Intl.DateTimeFormat().resolvedOptions().calendar;
+assert.notSameValue(localeCalendar, "iso8601", "no locale has the ISO calendar");
+
+const sameCalendarInstance = Temporal.PlainMonthDay.from({ monthCode: "M01", day: 1, calendar: localeCalendar });
+const result = sameCalendarInstance.toLocaleString();
+assert.sameValue(typeof result, "string", "toLocaleString() succeeds when instance has the same calendar as locale");
+
+// Pick a different calendar that is not ISO and not the locale's calendar
+const calendars = new Set(Intl.supportedValuesOf("calendar"));
+calendars.delete("iso8601");
+calendars.delete(localeCalendar);
+const differentCalendar = calendars.values().next().value;
+
+const differentCalendarInstance = Temporal.PlainMonthDay.from({ monthCode: "M01", day: 1, calendar: differentCalendar });
+assert.throws(RangeError, () => differentCalendarInstance.toLocaleString(), "calendar mismatch");
+
+const isoInstance = Temporal.PlainMonthDay.from({ monthCode: "M01", day: 1, calendar: "iso8601" });
+assert.throws(RangeError, () => isoInstance.toLocaleString(), "calendar mismatch even when instance has the ISO calendar")
diff --git a/test/intl402/Temporal/PlainYearMonth/prototype/toLocaleString/calendar-mismatch.js b/test/intl402/Temporal/PlainYearMonth/prototype/toLocaleString/calendar-mismatch.js
new file mode 100644
index 0000000000..6785efd362
--- /dev/null
+++ b/test/intl402/Temporal/PlainYearMonth/prototype/toLocaleString/calendar-mismatch.js
@@ -0,0 +1,27 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plainyearmonth.prototype.tolocalestring
+description: Calendar must match the locale calendar
+features: [Temporal, Intl-enumeration]
+---*/
+
+const localeCalendar = new Intl.DateTimeFormat().resolvedOptions().calendar;
+assert.notSameValue(localeCalendar, "iso8601", "no locale has the ISO calendar");
+
+const sameCalendarInstance = new Temporal.PlainDate(2000, 1, 1, localeCalendar).toPlainYearMonth();
+const result = sameCalendarInstance.toLocaleString();
+assert.sameValue(typeof result, "string", "toLocaleString() succeeds when instance has the same calendar as locale");
+
+// Pick a different calendar that is not ISO and not the locale's calendar
+const calendars = new Set(Intl.supportedValuesOf("calendar"));
+calendars.delete("iso8601");
+calendars.delete(localeCalendar);
+const differentCalendar = calendars.values().next().value;
+
+const differentCalendarInstance = new Temporal.PlainDate(2000, 1, 1, differentCalendar).toPlainYearMonth();
+assert.throws(RangeError, () => differentCalendarInstance.toLocaleString(), "calendar mismatch");
+
+const isoInstance = new Temporal.PlainDate(2000, 1, 1, "iso8601").toPlainYearMonth();
+assert.throws(RangeError, () => isoInstance.toLocaleString(), "calendar mismatch even when instance has the ISO calendar")
diff --git a/test/staging/Intl402/Temporal/old/date-toLocaleString.js b/test/staging/Intl402/Temporal/old/date-toLocaleString.js
index 282b22850e..8b90b223cc 100644
--- a/test/staging/Intl402/Temporal/old/date-toLocaleString.js
+++ b/test/staging/Intl402/Temporal/old/date-toLocaleString.js
@@ -31,28 +31,3 @@ assert.sameValue(date.toLocaleString("en-US", { timeZoneName: "long" }), "11/18/
 assert.sameValue(date.toLocaleString("en-US", { hour: "numeric" }), "11/18/1976");
 assert.sameValue(date.toLocaleString("en-US", { minute: "numeric" }), "11/18/1976");
 assert.sameValue(date.toLocaleString("en-US", { second: "numeric" }), "11/18/1976");
-
-// works when the object's calendar is the same as the locale's calendar
-var d = Temporal.PlainDate.from({
-  era: "showa",
-  eraYear: 51,
-  month: 11,
-  day: 18,
-  calendar: "japanese"
-});
-var result = d.toLocaleString("en-US-u-ca-japanese");
-assert(result === "11/18/51" || result === "11/18/51 S");
-
-// adopts the locale's calendar when the object's calendar is ISO
-var d = Temporal.PlainDate.from("1976-11-18");
-var result = d.toLocaleString("en-US-u-ca-japanese");
-assert(result === "11/18/51" || result === "11/18/51 S");
-
-// throws when the calendars are different and not ISO
-var d = Temporal.PlainDate.from({
-  year: 1976,
-  month: 11,
-  day: 18,
-  calendar: "gregory"
-});
-assert.throws(RangeError, () => d.toLocaleString("en-US-u-ca-japanese"));
diff --git a/test/staging/Intl402/Temporal/old/datetime-toLocaleString.js b/test/staging/Intl402/Temporal/old/datetime-toLocaleString.js
index 65a7bcdbef..c5889e0ecb 100644
--- a/test/staging/Intl402/Temporal/old/datetime-toLocaleString.js
+++ b/test/staging/Intl402/Temporal/old/datetime-toLocaleString.js
@@ -49,34 +49,3 @@ assert.sameValue(
   `${dstStart.toLocaleString("en-US", { timeZone: "America/Los_Angeles" })}`,
   `3/8/2020, 3:30:00${usDayPeriodSpace}AM`
 );
-
-// works when the object's calendar is the same as the locale's calendar
-var dt = Temporal.PlainDateTime.from({
-  era: "showa",
-  eraYear: 51,
-  month: 11,
-  day: 18,
-  hour: 15,
-  minute: 23,
-  second: 30,
-  calendar: "japanese"
-});
-var result = dt.toLocaleString("en-US-u-ca-japanese");
-assert(result === `11/18/51, 3:23:30${usDayPeriodSpace}PM` || result === `11/18/51 S, 3:23:30${usDayPeriodSpace}PM`);
-
-// adopts the locale's calendar when the object's calendar is ISO
-var dt = Temporal.PlainDateTime.from("1976-11-18T15:23:30");
-var result = dt.toLocaleString("en-US-u-ca-japanese");
-assert(result === `11/18/51, 3:23:30${usDayPeriodSpace}PM` || result === `11/18/51 S, 3:23:30${usDayPeriodSpace}PM`);
-
-// throws when the calendars are different and not ISO
-var dt = Temporal.PlainDateTime.from({
-  year: 1976,
-  month: 11,
-  day: 18,
-  hour: 15,
-  minute: 23,
-  second: 30,
-  calendar: "gregory"
-});
-assert.throws(RangeError, () => dt.toLocaleString("en-US-u-ca-japanese"));
diff --git a/test/staging/Intl402/Temporal/old/monthday-toLocaleString.js b/test/staging/Intl402/Temporal/old/monthday-toLocaleString.js
index d064ef2736..8b21023074 100644
--- a/test/staging/Intl402/Temporal/old/monthday-toLocaleString.js
+++ b/test/staging/Intl402/Temporal/old/monthday-toLocaleString.js
@@ -26,18 +26,3 @@ assert.sameValue(monthday.toLocaleString("en-US", { hour: "numeric" }), "11/18")
 assert.sameValue(monthday.toLocaleString("en-US", { minute: "numeric" }), "11/18");
 assert.sameValue(monthday.toLocaleString("en-US", { second: "numeric" }), "11/18");
 assert.sameValue(monthday.toLocaleString("en-US", { weekday: "long" }), "11/18");
-
-// works when the object's calendar is the same as the locale's calendar
-var md = Temporal.PlainMonthDay.from({
-  monthCode: "M11",
-  day: 18,
-  calendar: "japanese"
-});
-assert.sameValue(`${ md.toLocaleString("en-US-u-ca-japanese") }`, "11/18");
-
-// throws when the calendar is not equal to the locale calendar
-var mdISO = Temporal.PlainMonthDay.from({
-  month: 11,
-  day: 18
-});
-assert.throws(RangeError, () => mdISO.toLocaleString("en-US-u-ca-japanese"));
diff --git a/test/staging/Intl402/Temporal/old/yearmonth-toLocaleString.js b/test/staging/Intl402/Temporal/old/yearmonth-toLocaleString.js
index 8e8a1d3146..fc80d3bcac 100644
--- a/test/staging/Intl402/Temporal/old/yearmonth-toLocaleString.js
+++ b/test/staging/Intl402/Temporal/old/yearmonth-toLocaleString.js
@@ -37,20 +37,3 @@ assert.sameValue(yearmonth.toLocaleString("en-US", { hour: "numeric" }), "11/197
 assert.sameValue(yearmonth.toLocaleString("en-US", { minute: "numeric" }), "11/1976");
 assert.sameValue(yearmonth.toLocaleString("en-US", { second: "numeric" }), "11/1976");
 assert.sameValue(yearmonth.toLocaleString("en-US", { weekday: "long" }), "11/1976");
-
-// works when the object's calendar is the same as the locale's calendar
-var ym = Temporal.PlainYearMonth.from({
-  era: "showa",
-  eraYear: 51,
-  month: 11,
-  calendar: "japanese"
-});
-var result = ym.toLocaleString("en-US-u-ca-japanese");
-assert(result === "11/51" || result === "11/51 S");
-
-// throws when the calendar is not equal to the locale calendar
-var ymISO = Temporal.PlainYearMonth.from({
-  year: 1976,
-  month: 11
-});
-assert.throws(RangeError, () => ymISO.toLocaleString("en-US-u-ca-japanese"));