diff --git a/test/built-ins/Temporal/Instant/prototype/toLocaleString/era.js b/test/built-ins/Temporal/Instant/prototype/toLocaleString/era.js
new file mode 100644
index 00000000000..6daee3deec3
--- /dev/null
+++ b/test/built-ins/Temporal/Instant/prototype/toLocaleString/era.js
@@ -0,0 +1,15 @@
+// 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.instant.prototype.tolocalestring
+description: >
+    If era option and no other options are provided to toLocaleString,
+    Instant should be foramtted with default options
+features: [Temporal]
+locale: [en]
+---*/
+
+const instant = new Temporal.Instant(0n);
+
+assert(instant.toLocaleString("en", { era: "narrow", timeZone: "UTC" }).startsWith("1"), "toLocaleString on an Instant with era option should work");
diff --git a/test/built-ins/Temporal/PlainDate/prototype/toLocaleString/era.js b/test/built-ins/Temporal/PlainDate/prototype/toLocaleString/era.js
new file mode 100644
index 00000000000..d6ab1e8fd96
--- /dev/null
+++ b/test/built-ins/Temporal/PlainDate/prototype/toLocaleString/era.js
@@ -0,0 +1,15 @@
+// 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.prototype.tolocalestring
+description: >
+    If era option and no other options are provided to toLocaleString,
+    PlainDate should be foramtted with default options
+features: [Temporal]
+locale: [en]
+---*/
+
+const date = new Temporal.PlainDate(2000, 5, 2, "gregory");
+
+assert(date.toLocaleString("en", { era: "narrow" }).startsWith("5"), "toLocaleString on a PlainDate with era option should work");
diff --git a/test/built-ins/Temporal/PlainDateTime/prototype/toLocaleString/era.js b/test/built-ins/Temporal/PlainDateTime/prototype/toLocaleString/era.js
new file mode 100644
index 00000000000..eace04aed87
--- /dev/null
+++ b/test/built-ins/Temporal/PlainDateTime/prototype/toLocaleString/era.js
@@ -0,0 +1,15 @@
+// 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.plaindatetime.prototype.tolocalestring
+description: >
+    If era option and no other options are provided to toLocaleString,
+    PlainDateTime should be foramtted with default options
+features: [Temporal]
+locale: [en]
+---*/
+
+date = new Temporal.PlainDateTime(2000, 5, 2, 14, 46, 0, 0, 0, 0, "gregory");
+
+assert(date.toLocaleString("en", { era: "narrow" }).startsWith("5"), "toLocaleString on a PlainDateTime with era option should work");
diff --git a/test/built-ins/Temporal/PlainMonthDay/prototype/toLocaleString/era.js b/test/built-ins/Temporal/PlainMonthDay/prototype/toLocaleString/era.js
new file mode 100644
index 00000000000..d4f51b418ab
--- /dev/null
+++ b/test/built-ins/Temporal/PlainMonthDay/prototype/toLocaleString/era.js
@@ -0,0 +1,15 @@
+// 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.plainmonthday.prototype.tolocalestring
+description: >
+    If era option and no other options are provided to toLocaleString,
+    PlainMonthDay should be foramtted with default options
+features: [Temporal]
+locale: [en]
+---*/
+
+const date = new Temporal.PlainMonthDay(5, 2, "gregory");
+
+assert(date.toLocaleString("en", { era: "narrow" }).startsWith("5"), "toLocaleString on a PlainMonthDay with era option should work");
diff --git a/test/built-ins/Temporal/PlainTime/prototype/toLocaleString/era.js b/test/built-ins/Temporal/PlainTime/prototype/toLocaleString/era.js
new file mode 100644
index 00000000000..7f5b59fa3b4
--- /dev/null
+++ b/test/built-ins/Temporal/PlainTime/prototype/toLocaleString/era.js
@@ -0,0 +1,18 @@
+// 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.plaintime.prototype.tolocalestring
+description: >
+    If era option and no other options are provided to toLocaleString,
+    PlainTime should be foramtted with default options
+features: [Temporal]
+locale: [en]
+---*/
+
+const date = new Temporal.PlainTime(14, 46);
+
+const result = date.toLocaleString("en", { era: "narrow" });
+
+assert(result.startsWith("2"), "toLocaleString on a PlainTime with era option should work");
+assert(!result.includes("A"), "era should be ignored when formatting a PlainTime");
diff --git a/test/built-ins/Temporal/PlainYearMonth/prototype/toLocaleString/era.js b/test/built-ins/Temporal/PlainYearMonth/prototype/toLocaleString/era.js
new file mode 100644
index 00000000000..7fe4beece1b
--- /dev/null
+++ b/test/built-ins/Temporal/PlainYearMonth/prototype/toLocaleString/era.js
@@ -0,0 +1,15 @@
+// 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.prototype.tolocalestring
+description: >
+    If era option and no other options are provided to toLocaleString,
+    PlainYearMonth should be foramtted with default options
+features: [Temporal]
+locale: [en]
+---*/
+
+const date = new Temporal.PlainYearMonth(2000, 5, "gregory");
+
+assert(date.toLocaleString("en", { era: "narrow" }).startsWith("5"), "toLocaleString on a PlainYearMonth with era option should work");
diff --git a/test/built-ins/Temporal/ZonedDateTime/prototype/toLocaleString/era.js b/test/built-ins/Temporal/ZonedDateTime/prototype/toLocaleString/era.js
new file mode 100644
index 00000000000..1495c9b62a3
--- /dev/null
+++ b/test/built-ins/Temporal/ZonedDateTime/prototype/toLocaleString/era.js
@@ -0,0 +1,15 @@
+// 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.zoneddatetime.prototype.tolocalestring
+description: >
+    If era option and no other options are provided to toLocaleString,
+    ZonedDateTime should be foramtted with default options
+features: [Temporal]
+locale: [en]
+---*/
+
+const zdt = new Temporal.ZonedDateTime(0n, "UTC");
+
+assert(zdt.toLocaleString("en", { era: "narrow" }).startsWith("1"), "toLocaleString on a ZonedDateTime with era option should work");
diff --git a/test/intl402/DateTimeFormat/prototype/format/temporal-objects-format-with-era.js b/test/intl402/DateTimeFormat/prototype/format/temporal-objects-format-with-era.js
new file mode 100644
index 00000000000..be3ebcd96c1
--- /dev/null
+++ b/test/intl402/DateTimeFormat/prototype/format/temporal-objects-format-with-era.js
@@ -0,0 +1,20 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-datetime-format-functions
+description: >
+  If era option and no other options are provided to DateTimeFormat constructor,
+  objects should be formatted with default options
+features: [Temporal]
+locale: [en]
+---*/
+
+const formatter = new Intl.DateTimeFormat(["en"], { era: "narrow", timeZone: "UTC" });
+
+assert(formatter.format(new Temporal.PlainDate(2025, 11, 4)).startsWith("11"), "formatting a PlainDate should work");
+assert(formatter.format(new Temporal.PlainYearMonth(2025, 11, "gregory")).startsWith("11"), "formatting a PlainYearMonth should work");
+assert(formatter.format(new Temporal.PlainMonthDay(11, 4, "gregory")).startsWith("11"), "formatting a PlainMonthDay should work");
+assert(formatter.format(new Temporal.PlainTime(14, 46)).startsWith("2"), "formatting a PlainTime should work");
+assert(formatter.format(new Temporal.PlainDateTime(2025, 11, 4, 14, 46)).startsWith("11"), "formatting a PlainDateTime should work");
+assert(formatter.format(new Temporal.Instant(0n)).startsWith("1"), "formatting an Instant should work");
diff --git a/test/intl402/DateTimeFormat/prototype/formatRange/temporal-objects-format-with-era.js b/test/intl402/DateTimeFormat/prototype/formatRange/temporal-objects-format-with-era.js
new file mode 100644
index 00000000000..be3ebcd96c1
--- /dev/null
+++ b/test/intl402/DateTimeFormat/prototype/formatRange/temporal-objects-format-with-era.js
@@ -0,0 +1,20 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-datetime-format-functions
+description: >
+  If era option and no other options are provided to DateTimeFormat constructor,
+  objects should be formatted with default options
+features: [Temporal]
+locale: [en]
+---*/
+
+const formatter = new Intl.DateTimeFormat(["en"], { era: "narrow", timeZone: "UTC" });
+
+assert(formatter.format(new Temporal.PlainDate(2025, 11, 4)).startsWith("11"), "formatting a PlainDate should work");
+assert(formatter.format(new Temporal.PlainYearMonth(2025, 11, "gregory")).startsWith("11"), "formatting a PlainYearMonth should work");
+assert(formatter.format(new Temporal.PlainMonthDay(11, 4, "gregory")).startsWith("11"), "formatting a PlainMonthDay should work");
+assert(formatter.format(new Temporal.PlainTime(14, 46)).startsWith("2"), "formatting a PlainTime should work");
+assert(formatter.format(new Temporal.PlainDateTime(2025, 11, 4, 14, 46)).startsWith("11"), "formatting a PlainDateTime should work");
+assert(formatter.format(new Temporal.Instant(0n)).startsWith("1"), "formatting an Instant should work");
diff --git a/test/intl402/DateTimeFormat/prototype/formatRangeToParts/temporal-objects-format-with-era.js b/test/intl402/DateTimeFormat/prototype/formatRangeToParts/temporal-objects-format-with-era.js
new file mode 100644
index 00000000000..15762a93c4b
--- /dev/null
+++ b/test/intl402/DateTimeFormat/prototype/formatRangeToParts/temporal-objects-format-with-era.js
@@ -0,0 +1,29 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-datetime-format-functions
+description: >
+  If era option and no other options are provided to DateTimeFormat constructor,
+  objects should be formatted with default options
+features: [Temporal]
+locale: [en]
+---*/
+
+const formatter = new Intl.DateTimeFormat(["en"], { era: "narrow", timeZone: "UTC" });
+
+function checkEra(parts) {
+    for (let part of parts) {
+        if (part.type === 'era' && part.value.startsWith('A'))
+            return true;
+    }
+    return false;
+}
+
+assert(checkEra(formatter.formatRangeToParts(new Temporal.PlainDate(2025, 11, 4), new Temporal.PlainDate(2025, 11, 5))), "formatting a PlainDate should work");
+assert(checkEra(formatter.formatRangeToParts(new Temporal.PlainDate(2025, 11, 4), new Temporal.PlainDate(2025, 11, 5))), "formatting a PlainDate should work");
+assert(checkEra(formatter.formatRangeToParts(new Temporal.PlainYearMonth(2025, 11, "gregory"), new Temporal.PlainYearMonth(2025, 12, "gregory"))), "formatting a PlainYearMonth should work");
+assert(checkEra(formatter.formatRangeToParts(new Temporal.PlainMonthDay(11, 4, "gregory"), new Temporal.PlainMonthDay(11, 14, "gregory"))), "formatting a PlainMonthDay should work");
+assert(!checkEra(formatter.formatRangeToParts(new Temporal.PlainTime(14, 46), new Temporal.PlainTime(17, 46))), "formatting a PlainTime should work");
+assert(checkEra(formatter.formatRangeToParts(new Temporal.PlainDateTime(2025, 11, 4, 14, 46), new Temporal.PlainDateTime(2025, 11, 15, 14, 47))), "formatting a PlainDateTime should work");
+assert(checkEra(formatter.formatRangeToParts(new Temporal.Instant(0n), new Temporal.Instant(1000000000n))), "formatting an Instant should work");
diff --git a/test/intl402/DateTimeFormat/prototype/formatToParts/temporal-objects-format-with-era.js b/test/intl402/DateTimeFormat/prototype/formatToParts/temporal-objects-format-with-era.js
new file mode 100644
index 00000000000..8ae3eb48b13
--- /dev/null
+++ b/test/intl402/DateTimeFormat/prototype/formatToParts/temporal-objects-format-with-era.js
@@ -0,0 +1,28 @@
+// Copyright (C) 2025 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-datetime-format-functions
+description: >
+  If era option and no other options are provided to DateTimeFormat constructor,
+  objects should be formatted with default options
+features: [Temporal]
+locale: [en]
+---*/
+
+const formatter = new Intl.DateTimeFormat(["en"], { era: "narrow", timeZone: "UTC" });
+
+function checkEra(parts) {
+    for (let part of parts) {
+        if (part.type === 'era' && part.value.startsWith('A'))
+            return true;
+    }
+    return false;
+}
+
+assert(checkEra(formatter.formatToParts(new Temporal.PlainDate(2025, 11, 4))), "formatting a PlainDate should work");
+assert(checkEra(formatter.formatToParts(new Temporal.PlainYearMonth(2025, 11, "gregory"))), "formatting a PlainYearMonth should work");
+assert(checkEra(formatter.formatToParts(new Temporal.PlainMonthDay(11, 4, "gregory"))), "formatting a PlainMonthDay should work");
+assert(!checkEra(formatter.formatToParts(new Temporal.PlainTime(14, 46))), "formatting a PlainTime should work");
+assert(checkEra(formatter.formatToParts(new Temporal.PlainDateTime(2025, 11, 4, 14, 46))), "formatting a PlainDateTime should work");
+assert(checkEra(formatter.formatToParts(new Temporal.Instant(0n))), "formatting an Instant should work");