diff --git a/Userland/Libraries/LibJS/Runtime/Temporal/PlainDatePrototype.cpp b/Userland/Libraries/LibJS/Runtime/Temporal/PlainDatePrototype.cpp
index eb57556a9d..d486089e3c 100644
--- a/Userland/Libraries/LibJS/Runtime/Temporal/PlainDatePrototype.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Temporal/PlainDatePrototype.cpp
@@ -5,6 +5,7 @@
  */
 
 #include <LibJS/Runtime/GlobalObject.h>
+#include <LibJS/Runtime/Temporal/PlainDate.h>
 #include <LibJS/Runtime/Temporal/PlainDatePrototype.h>
 
 namespace JS::Temporal {
@@ -23,6 +24,34 @@ void PlainDatePrototype::initialize(GlobalObject& global_object)
 
     // 3.3.2 Temporal.PlainDate.prototype[ @@toStringTag ], https://tc39.es/proposal-temporal/#sec-temporal.plaindate.prototype-@@tostringtag
     define_direct_property(*vm.well_known_symbol_to_string_tag(), js_string(vm.heap(), "Temporal.PlainDate"), Attribute::Configurable);
+
+    define_native_accessor(vm.names.calendar, calendar_getter, {}, Attribute::Configurable);
+}
+
+static PlainDate* typed_this(GlobalObject& global_object)
+{
+    auto& vm = global_object.vm();
+    auto* this_object = vm.this_value(global_object).to_object(global_object);
+    if (!this_object)
+        return {};
+    if (!is<PlainDate>(this_object)) {
+        vm.throw_exception<TypeError>(global_object, ErrorType::NotA, "Temporal.PlainDate");
+        return {};
+    }
+    return static_cast<PlainDate*>(this_object);
+}
+
+// 3.3.3 get Temporal.PlainDate.prototype.calendar, https://tc39.es/proposal-temporal/#sec-get-temporal.plaindate.prototype.calendar
+JS_DEFINE_NATIVE_FUNCTION(PlainDatePrototype::calendar_getter)
+{
+    // 1. Let temporalDate be the this value.
+    // Perform ? RequireInternalSlot(temporalDate, [[InitializedTemporalDate]]).
+    auto* temporal_date = typed_this(global_object);
+    if (vm.exception())
+        return {};
+
+    // 3. Return temporalDate.[[Calendar]].
+    return Value(&temporal_date->calendar());
 }
 
 }
diff --git a/Userland/Libraries/LibJS/Runtime/Temporal/PlainDatePrototype.h b/Userland/Libraries/LibJS/Runtime/Temporal/PlainDatePrototype.h
index 88c5fbd4b9..69f93afa6f 100644
--- a/Userland/Libraries/LibJS/Runtime/Temporal/PlainDatePrototype.h
+++ b/Userland/Libraries/LibJS/Runtime/Temporal/PlainDatePrototype.h
@@ -17,6 +17,9 @@ public:
     explicit PlainDatePrototype(GlobalObject&);
     virtual void initialize(GlobalObject&) override;
     virtual ~PlainDatePrototype() override = default;
+
+private:
+    JS_DECLARE_NATIVE_FUNCTION(calendar_getter);
 };
 
 }
diff --git a/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainDate/PlainDate.prototype.calendar.js b/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainDate/PlainDate.prototype.calendar.js
new file mode 100644
index 0000000000..2a122a82fd
--- /dev/null
+++ b/Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainDate/PlainDate.prototype.calendar.js
@@ -0,0 +1,15 @@
+describe("correct behavior", () => {
+    test("basic functionality", () => {
+        const calendar = { hello: "friends" };
+        const plain_date = new Temporal.PlainDate(1, 1, 1, calendar);
+        expect(plain_date.calendar).toBe(calendar);
+    });
+});
+
+test("errors", () => {
+    test("this value must be a Temporal.Duration object", () => {
+        expect(() => {
+            Reflect.get(Temporal.PlainDate.prototype, "calendar", "foo");
+        }).toThrowWithMessage(TypeError, "Not a Temporal.PlainDate");
+    });
+});