diff --git a/Libraries/LibJS/Runtime/Temporal/PlainDateTimePrototype.cpp b/Libraries/LibJS/Runtime/Temporal/PlainDateTimePrototype.cpp
index ae665cf88f1..0814ca7d31b 100644
--- a/Libraries/LibJS/Runtime/Temporal/PlainDateTimePrototype.cpp
+++ b/Libraries/LibJS/Runtime/Temporal/PlainDateTimePrototype.cpp
@@ -9,6 +9,7 @@
 #include <LibJS/Runtime/Temporal/AbstractOperations.h>
 #include <LibJS/Runtime/Temporal/Calendar.h>
 #include <LibJS/Runtime/Temporal/Duration.h>
+#include <LibJS/Runtime/Temporal/PlainDate.h>
 #include <LibJS/Runtime/Temporal/PlainDateTimePrototype.h>
 #include <LibJS/Runtime/Temporal/PlainTime.h>
 
@@ -67,6 +68,8 @@ void PlainDateTimePrototype::initialize(Realm& realm)
     define_native_function(realm, vm.names.toString, to_string, 0, attr);
     define_native_function(realm, vm.names.toLocaleString, to_locale_string, 0, attr);
     define_native_function(realm, vm.names.toJSON, to_json, 0, attr);
+    define_native_function(realm, vm.names.toPlainDate, to_plain_date, 0, attr);
+    define_native_function(realm, vm.names.toPlainTime, to_plain_time, 0, attr);
 }
 
 // 5.3.3 get Temporal.PlainDateTime.prototype.calendarId, https://tc39.es/proposal-temporal/#sec-get-temporal.plaindatetime.prototype.calendarid
@@ -547,4 +550,26 @@ JS_DEFINE_NATIVE_FUNCTION(PlainDateTimePrototype::to_json)
     return PrimitiveString::create(vm, iso_date_time_to_string(date_time->iso_date_time(), date_time->calendar(), Auto {}, ShowCalendar::Auto));
 }
 
+// 5.3.39 Temporal.PlainDateTime.prototype.toPlainDate ( ), https://tc39.es/proposal-temporal/#sec-temporal.plaindatetime.prototype.toplaindate
+JS_DEFINE_NATIVE_FUNCTION(PlainDateTimePrototype::to_plain_date)
+{
+    // 1. Let dateTime be the this value.
+    // 2. Perform ? RequireInternalSlot(dateTime, [[InitializedTemporalDateTime]]).
+    auto date_time = TRY(typed_this_object(vm));
+
+    // 3. Return ! CreateTemporalDate(dateTime.[[ISODateTime]].[[ISODate]], dateTime.[[Calendar]]).
+    return MUST(create_temporal_date(vm, date_time->iso_date_time().iso_date, date_time->calendar()));
+}
+
+// 5.3.40 Temporal.PlainDateTime.prototype.toPlainTime ( ), https://tc39.es/proposal-temporal/#sec-temporal.plaindatetime.prototype.toplaintime
+JS_DEFINE_NATIVE_FUNCTION(PlainDateTimePrototype::to_plain_time)
+{
+    // 1. Let dateTime be the this value.
+    // 2. Perform ? RequireInternalSlot(dateTime, [[InitializedTemporalDateTime]]).
+    auto date_time = TRY(typed_this_object(vm));
+
+    // 3. Return ! CreateTemporalTime(dateTime.[[ISODateTime]].[[Time]]).
+    return MUST(create_temporal_time(vm, date_time->iso_date_time().time));
+}
+
 }
diff --git a/Libraries/LibJS/Runtime/Temporal/PlainDateTimePrototype.h b/Libraries/LibJS/Runtime/Temporal/PlainDateTimePrototype.h
index 67dd8a31443..0091eeb3d29 100644
--- a/Libraries/LibJS/Runtime/Temporal/PlainDateTimePrototype.h
+++ b/Libraries/LibJS/Runtime/Temporal/PlainDateTimePrototype.h
@@ -57,6 +57,8 @@ private:
     JS_DECLARE_NATIVE_FUNCTION(to_string);
     JS_DECLARE_NATIVE_FUNCTION(to_locale_string);
     JS_DECLARE_NATIVE_FUNCTION(to_json);
+    JS_DECLARE_NATIVE_FUNCTION(to_plain_date);
+    JS_DECLARE_NATIVE_FUNCTION(to_plain_time);
 };
 
 }
diff --git a/Libraries/LibJS/Tests/builtins/Temporal/PlainDateTime/PlainDateTime.prototype.toPlainDate.js b/Libraries/LibJS/Tests/builtins/Temporal/PlainDateTime/PlainDateTime.prototype.toPlainDate.js
new file mode 100644
index 00000000000..7723de2a3b3
--- /dev/null
+++ b/Libraries/LibJS/Tests/builtins/Temporal/PlainDateTime/PlainDateTime.prototype.toPlainDate.js
@@ -0,0 +1,11 @@
+describe("normal behavior", () => {
+    test("length is 0", () => {
+        expect(Temporal.PlainDateTime.prototype.toPlainDate).toHaveLength(0);
+    });
+
+    test("basic functionality", () => {
+        const plainDateTime = new Temporal.PlainDateTime(2021, 7, 23, 0, 32, 18, 123, 456, 789);
+        const plainDate = plainDateTime.toPlainDate();
+        expect(plainDate.equals(new Temporal.PlainDate(2021, 7, 23))).toBeTrue();
+    });
+});
diff --git a/Libraries/LibJS/Tests/builtins/Temporal/PlainDateTime/PlainDateTime.prototype.toPlainTime.js b/Libraries/LibJS/Tests/builtins/Temporal/PlainDateTime/PlainDateTime.prototype.toPlainTime.js
new file mode 100644
index 00000000000..feb4839dc9b
--- /dev/null
+++ b/Libraries/LibJS/Tests/builtins/Temporal/PlainDateTime/PlainDateTime.prototype.toPlainTime.js
@@ -0,0 +1,16 @@
+describe("normal behavior", () => {
+    test("length is 0", () => {
+        expect(Temporal.PlainDateTime.prototype.toPlainTime).toHaveLength(0);
+    });
+
+    test("basic functionality", () => {
+        const plainDateTime = new Temporal.PlainDateTime(2021, 7, 31, 0, 32, 18, 123, 456, 789);
+        const plainTime = plainDateTime.toPlainTime();
+        expect(plainTime.hour).toBe(0);
+        expect(plainTime.minute).toBe(32);
+        expect(plainTime.second).toBe(18);
+        expect(plainTime.millisecond).toBe(123);
+        expect(plainTime.microsecond).toBe(456);
+        expect(plainTime.nanosecond).toBe(789);
+    });
+});