diff --git a/test/intl402/Temporal/PlainDate/from/remapping-era.js b/test/intl402/Temporal/PlainDate/from/remapping-era.js
new file mode 100644
index 0000000000..8484b275d0
--- /dev/null
+++ b/test/intl402/Temporal/PlainDate/from/remapping-era.js
@@ -0,0 +1,118 @@
+// Copyright (C) 2025 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.from
+description: Test remapping behaviour of regnal eras
+info: |
+  CalendarDateFromFields:
+  1. Perform ? CalendarResolveFields(_calendar_, _fields_, _date_).
+  2. Let result be ? CalendarDateToISO(_calendar_, _fields_, _overflow_).
+
+  CalendarResolveFields:
+  When the fields of _fields_ are inconsistent with respect to a non-unset
+  _fields_.[[Era]], it is recommended that _fields_.[[Era]] and
+  _fields_.[[EraYear]] be updated to resolve the inconsistency by lenient
+  interpretation of out-of-bounds values (rather than throwing a *RangeError*),
+  which is particularly useful for consistent interpretation of dates in
+  calendars with regnal eras.
+
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+// Based on a test originally by André Bargull <andre.bargull@gmail.com>
+
+// Notes:
+// - "heisei" era started January 8, 1989.
+// - "reiwa" era started May 1, 2019.
+
+for (const overflow of ["constrain", "reject"]) {
+  function test(fields) {
+    return Temporal.PlainDate.from({ ...fields, calendar: "japanese" }, { overflow });
+  }
+
+  // Reiwa era started in month 5 of the year, so the era of month 1 is remapped
+  // to be the correct one for the month.
+  TemporalHelpers.assertPlainDate(
+    test({ era: "reiwa", eraYear: 1, monthCode: "M01", day: 24 }),
+    2019, 1, "M01", 24,
+    "Reiwa 1 before May is mapped to Heisei 31",
+    "heisei", 31
+  );
+
+  // Reiwa era started on the first day of the month, so day 1 does not need
+  // remapping.
+  TemporalHelpers.assertPlainDate(
+    test({ era: "reiwa", eraYear: 1, monthCode: "M05", day: 1 }),
+    2019, 5, "M05", 1,
+    "05-01 Reiwa 1 is not remapped",
+    "reiwa", 1
+  );
+
+  // Heisei era started on the eighth day of the month. So on previous days the
+  // era is remapped to be the correct one for the day.
+  TemporalHelpers.assertPlainDate(
+    test({ era: "heisei", eraYear: 1, monthCode: "M01", day: 4 }),
+    1989, 1, "M01", 4,
+    "01-04 Heisei 1 is remapped to 01-04 Showa 64",
+    "showa", 64
+  );
+
+  // Era year past the end of the Heisei era is remapped to Reiwa era
+  TemporalHelpers.assertPlainDate(
+    test({ era: "heisei", eraYear: 37, monthCode: "M04", day: 25 }),
+    2025, 4, "M04", 25,
+    "Heisei 37 is remapped to Reiwa 7",
+    "reiwa", 7
+  );
+
+  // Zero year in a 1-based era is remapped to the previous era
+  TemporalHelpers.assertPlainDate(
+    test({ era: "reiwa", eraYear: 0, monthCode: "M04", day: 25 }),
+    2018, 4, "M04", 25,
+    "Reiwa 0 is remapped to Heisei 30",
+    "heisei", 30
+  );
+
+  // Negative year in a forward-counting era is remapped to the previous era
+  TemporalHelpers.assertPlainDate(
+    test({ era: "reiwa", eraYear: -20, monthCode: "M04", day: 25 }),
+    1998, 4, "M04", 25,
+    "Reiwa -20 is remapped to Heisei 10",
+    "heisei", 10
+  );
+
+  // Test the last two things for Gregorian eras as well
+  function testGregorian(fields) {
+    return Temporal.PlainDate.from({ ...fields, calendar: "gregory" }, { overflow });
+  }
+  TemporalHelpers.assertPlainDate(
+    testGregorian({ era: "ce", eraYear: 0, monthCode: "M04", day: 25 }),
+    0, 4, "M04", 25,
+    "0 CE is remapped to 1 BCE",
+    "bce", 1
+  );
+  TemporalHelpers.assertPlainDate(
+    testGregorian({ era: "ce", eraYear: -20, monthCode: "M04", day: 25 }),
+    -20, 4, "M04", 25,
+    "-20 CE is remapped to 21 BCE",
+    "bce", 21
+  );
+
+  // Zero year in a backwards-counting era is remapped to the next era
+  TemporalHelpers.assertPlainDate(
+    testGregorian({ era: "bce", eraYear: 0, monthCode: "M04", day: 25 }),
+    1, 4, "M04", 25,
+    "0 BCE is remapped to 1 CE",
+    "ce", 1
+  );
+
+  // Negative year in a backwards-counting era is remapped to the next era
+  TemporalHelpers.assertPlainDate(
+    testGregorian({ era: "bce", eraYear: -20, monthCode: "M04", day: 25 }),
+    21, 4, "M04", 25,
+    "-20 BCE is remapped to 21 CE",
+    "ce", 21
+  );
+}
diff --git a/test/intl402/Temporal/PlainYearMonth/from/remapping-era.js b/test/intl402/Temporal/PlainYearMonth/from/remapping-era.js
new file mode 100644
index 0000000000..6b8d9fec97
--- /dev/null
+++ b/test/intl402/Temporal/PlainYearMonth/from/remapping-era.js
@@ -0,0 +1,123 @@
+// Copyright (C) 2025 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plainyearmonth.from
+description: Test remapping behaviour of regnal eras
+info: |
+  CalendarYearMonthFromFields:
+  1. Perform ? CalendarResolveFields(_calendar_, _fields_, ~year-month~).
+  2. Let _firstDayIndex_ be the 1-based index of the first day of the month
+     described by _fields_ (i.e., 1 unless the month's first day is skipped by
+     this calendar.)
+  3. Set _fields_.[[Day]] to _firstDayIndex_.
+  4. Let result be ? CalendarDateToISO(_calendar_, _fields_, _overflow_).
+
+  CalendarResolveFields:
+  When the fields of _fields_ are inconsistent with respect to a non-unset
+  _fields_.[[Era]], it is recommended that _fields_.[[Era]] and
+  _fields_.[[EraYear]] be updated to resolve the inconsistency by lenient
+  interpretation of out-of-bounds values (rather than throwing a *RangeError*),
+  which is particularly useful for consistent interpretation of dates in
+  calendars with regnal eras.
+
+includes: [temporalHelpers.js]
+features: [Temporal]
+---*/
+
+// Based on a test originally by André Bargull <andre.bargull@gmail.com>
+
+// Notes:
+// - "heisei" era started January 8, 1989.
+// - "reiwa" era started May 1, 2019.
+
+for (const overflow of ["constrain", "reject"]) {
+  function test(fields) {
+    return Temporal.PlainYearMonth.from({ ...fields, calendar: "japanese" }, { overflow });
+  }
+
+  // Reiwa era started in month 5 of the year, so the era of month 1 is remapped
+  // to be the correct one for the month.
+  TemporalHelpers.assertPlainYearMonth(
+    test({ era: "reiwa", eraYear: 1, monthCode: "M01" }),
+    2019, 1, "M01",
+    "Reiwa 1 before May is mapped to Heisei 31",
+    "heisei", 31, /* reference day = */ 1
+  );
+
+  // Reiwa era started on the first day of the month, so the reference day 1
+  // does not need remapping.
+  TemporalHelpers.assertPlainYearMonth(
+    test({ era: "reiwa", eraYear: 1, monthCode: "M05" }),
+    2019, 5, "M05",
+    "reference day is 1",
+    "reiwa", 1, /* reference day = */ 1
+  );
+
+  // Heisei era started on the eighth day of the month, but PlainYearMonth
+  // references the first day of the month. So the era is remapped to be the
+  // correct one for the reference day.
+  TemporalHelpers.assertPlainYearMonth(
+    test({ era: "heisei", eraYear: 1, monthCode: "M01" }),
+    1989, 1, "M01",
+    "01-01 Heisei 1 is remapped to 01-01 Showa 64",
+    "showa", 64, /* reference day = */ 1
+  );
+
+  // Era year past the end of the Heisei era is remapped to Reiwa era
+  TemporalHelpers.assertPlainYearMonth(
+    test({ era: "heisei", eraYear: 37, monthCode: "M04" }),
+    2025, 4, "M04",
+    "Heisei 37 is remapped to Reiwa 7",
+    "reiwa", 7, /* reference day = */ 1
+  );
+
+  // Zero year in a 1-based era is remapped to the previous era
+  TemporalHelpers.assertPlainYearMonth(
+    test({ era: "reiwa", eraYear: 0, monthCode: "M04" }),
+    2018, 4, "M04",
+    "Reiwa 0 is remapped to Heisei 30",
+    "heisei", 30, /* reference day = */ 1
+  );
+
+  // Negative year in a forwards-counting era is remapped to the previous era
+  TemporalHelpers.assertPlainYearMonth(
+    test({ era: "reiwa", eraYear: -20, monthCode: "M04" }),
+    1998, 4, "M04",
+    "Reiwa -20 is remapped to Heisei 10",
+    "heisei", 10, /* reference day = */ 1
+  );
+
+  // Test the last two things for Gregorian eras as well
+  function testGregorian(fields) {
+    return Temporal.PlainYearMonth.from({ ...fields, calendar: "gregory" }, { overflow });
+  }
+  TemporalHelpers.assertPlainYearMonth(
+    testGregorian({ era: "ce", eraYear: 0, monthCode: "M04" }),
+    0, 4, "M04",
+    "0 CE is remapped to 1 BCE",
+    "bce", 1, /* reference day = */ 1
+  );
+  TemporalHelpers.assertPlainYearMonth(
+    testGregorian({ era: "ce", eraYear: -20, monthCode: "M04" }),
+    -20, 4, "M04",
+    "-20 CE is remapped to 21 BCE",
+    "bce", 21, /* reference day = */ 1
+  );
+
+  // Zero year in a backwards-counting era is remapped to the next era
+  TemporalHelpers.assertPlainYearMonth(
+    testGregorian({ era: "bce", eraYear: 0, monthCode: "M04" }),
+    1, 4, "M04",
+    "0 BCE is remapped to 1 CE",
+    "ce", 1, /* reference day = */ 1
+  );
+
+  // Negative year in a backwards-counting era is remapped to the next era
+  TemporalHelpers.assertPlainYearMonth(
+    testGregorian({ era: "bce", eraYear: -20, monthCode: "M04" }),
+    21, 4, "M04",
+    "-20 BCE is remapped to 21 CE",
+    "ce", 21, /* reference day = */ 1
+  );
+}