diff --git a/test/built-ins/Temporal/PlainDate/prototype/toPlainDateTime/argument-string-with-utc-designator.js b/test/built-ins/Temporal/PlainDate/prototype/toPlainDateTime/argument-string-with-utc-designator.js
index 65c1bc1c82..a35cf10b56 100644
--- a/test/built-ins/Temporal/PlainDate/prototype/toPlainDateTime/argument-string-with-utc-designator.js
+++ b/test/built-ins/Temporal/PlainDate/prototype/toPlainDateTime/argument-string-with-utc-designator.js
@@ -10,6 +10,8 @@ features: [Temporal, arrow-function]
 const invalidStrings = [
   "2019-10-01T09:00:00Z",
   "2019-10-01T09:00:00Z[UTC]",
+  "09:00:00Z[UTC]",
+  "09:00:00Z",
 ];
 const instance = new Temporal.PlainDate(2000, 5, 2);
 invalidStrings.forEach((arg) => {
diff --git a/test/built-ins/Temporal/PlainDate/prototype/toZonedDateTime/argument-string-with-utc-designator.js b/test/built-ins/Temporal/PlainDate/prototype/toZonedDateTime/argument-string-with-utc-designator.js
index ee1fa639c0..8529d75314 100644
--- a/test/built-ins/Temporal/PlainDate/prototype/toZonedDateTime/argument-string-with-utc-designator.js
+++ b/test/built-ins/Temporal/PlainDate/prototype/toZonedDateTime/argument-string-with-utc-designator.js
@@ -10,6 +10,8 @@ features: [Temporal, arrow-function]
 const invalidStrings = [
   "2019-10-01T09:00:00Z",
   "2019-10-01T09:00:00Z[UTC]",
+  "09:00:00Z[UTC]",
+  "09:00:00Z",
 ];
 const instance = new Temporal.PlainDate(2000, 5, 2);
 invalidStrings.forEach((arg) => {
diff --git a/test/built-ins/Temporal/PlainDateTime/prototype/withPlainTime/argument-string-with-utc-designator.js b/test/built-ins/Temporal/PlainDateTime/prototype/withPlainTime/argument-string-with-utc-designator.js
index 80baeb2ea5..7412a9ebad 100644
--- a/test/built-ins/Temporal/PlainDateTime/prototype/withPlainTime/argument-string-with-utc-designator.js
+++ b/test/built-ins/Temporal/PlainDateTime/prototype/withPlainTime/argument-string-with-utc-designator.js
@@ -10,6 +10,8 @@ features: [Temporal, arrow-function]
 const invalidStrings = [
   "2019-10-01T09:00:00Z",
   "2019-10-01T09:00:00Z[UTC]",
+  "09:00:00Z[UTC]",
+  "09:00:00Z",
 ];
 const instance = new Temporal.PlainDateTime(2000, 5, 2, 12, 34, 56, 987, 654, 321);
 invalidStrings.forEach((arg) => {
diff --git a/test/built-ins/Temporal/PlainTime/compare/argument-string-with-utc-designator.js b/test/built-ins/Temporal/PlainTime/compare/argument-string-with-utc-designator.js
index 61b28a61f5..84634a1c4b 100644
--- a/test/built-ins/Temporal/PlainTime/compare/argument-string-with-utc-designator.js
+++ b/test/built-ins/Temporal/PlainTime/compare/argument-string-with-utc-designator.js
@@ -10,6 +10,8 @@ features: [Temporal, arrow-function]
 const invalidStrings = [
   "2019-10-01T09:00:00Z",
   "2019-10-01T09:00:00Z[UTC]",
+  "09:00:00Z[UTC]",
+  "09:00:00Z",
 ];
 const plainTime = new Temporal.PlainTime();
 invalidStrings.forEach((arg) => {
diff --git a/test/built-ins/Temporal/PlainTime/from/argument-string-with-utc-designator.js b/test/built-ins/Temporal/PlainTime/from/argument-string-with-utc-designator.js
index 70e7b22506..215996e555 100644
--- a/test/built-ins/Temporal/PlainTime/from/argument-string-with-utc-designator.js
+++ b/test/built-ins/Temporal/PlainTime/from/argument-string-with-utc-designator.js
@@ -10,6 +10,8 @@ features: [Temporal, arrow-function]
 const invalidStrings = [
   "2019-10-01T09:00:00Z",
   "2019-10-01T09:00:00Z[UTC]",
+  "09:00:00Z[UTC]",
+  "09:00:00Z",
 ];
 invalidStrings.forEach((arg) => {
   assert.throws(
diff --git a/test/built-ins/Temporal/PlainTime/prototype/equals/argument-string-with-utc-designator.js b/test/built-ins/Temporal/PlainTime/prototype/equals/argument-string-with-utc-designator.js
index 8ea64a6f57..894824ba1e 100644
--- a/test/built-ins/Temporal/PlainTime/prototype/equals/argument-string-with-utc-designator.js
+++ b/test/built-ins/Temporal/PlainTime/prototype/equals/argument-string-with-utc-designator.js
@@ -10,6 +10,8 @@ features: [Temporal, arrow-function]
 const invalidStrings = [
   "2019-10-01T09:00:00Z",
   "2019-10-01T09:00:00Z[UTC]",
+  "09:00:00Z[UTC]",
+  "09:00:00Z",
 ];
 const instance = new Temporal.PlainTime(12, 34, 56, 987, 654, 321);
 invalidStrings.forEach((arg) => {
diff --git a/test/built-ins/Temporal/PlainTime/prototype/since/argument-string-with-utc-designator.js b/test/built-ins/Temporal/PlainTime/prototype/since/argument-string-with-utc-designator.js
index ccc946fbc5..54deaec9d0 100644
--- a/test/built-ins/Temporal/PlainTime/prototype/since/argument-string-with-utc-designator.js
+++ b/test/built-ins/Temporal/PlainTime/prototype/since/argument-string-with-utc-designator.js
@@ -10,6 +10,8 @@ features: [Temporal, arrow-function]
 const invalidStrings = [
   "2019-10-01T09:00:00Z",
   "2019-10-01T09:00:00Z[UTC]",
+  "09:00:00Z[UTC]",
+  "09:00:00Z",
 ];
 const instance = new Temporal.PlainTime(12, 34, 56, 987, 654, 321);
 invalidStrings.forEach((arg) => {
diff --git a/test/built-ins/Temporal/PlainTime/prototype/until/argument-string-with-utc-designator.js b/test/built-ins/Temporal/PlainTime/prototype/until/argument-string-with-utc-designator.js
index a64138a1a1..121ce49f18 100644
--- a/test/built-ins/Temporal/PlainTime/prototype/until/argument-string-with-utc-designator.js
+++ b/test/built-ins/Temporal/PlainTime/prototype/until/argument-string-with-utc-designator.js
@@ -10,6 +10,8 @@ features: [Temporal, arrow-function]
 const invalidStrings = [
   "2019-10-01T09:00:00Z",
   "2019-10-01T09:00:00Z[UTC]",
+  "09:00:00Z[UTC]",
+  "09:00:00Z",
 ];
 const instance = new Temporal.PlainTime(12, 34, 56, 987, 654, 321);
 invalidStrings.forEach((arg) => {
diff --git a/test/built-ins/Temporal/ZonedDateTime/prototype/withPlainTime/argument-string-with-utc-designator.js b/test/built-ins/Temporal/ZonedDateTime/prototype/withPlainTime/argument-string-with-utc-designator.js
index f821197cc4..87434d30c2 100644
--- a/test/built-ins/Temporal/ZonedDateTime/prototype/withPlainTime/argument-string-with-utc-designator.js
+++ b/test/built-ins/Temporal/ZonedDateTime/prototype/withPlainTime/argument-string-with-utc-designator.js
@@ -10,6 +10,8 @@ features: [Temporal, arrow-function]
 const invalidStrings = [
   "2019-10-01T09:00:00Z",
   "2019-10-01T09:00:00Z[UTC]",
+  "09:00:00Z[UTC]",
+  "09:00:00Z",
 ];
 const instance = new Temporal.ZonedDateTime(1_000_000_000_000_000_000n, "UTC");
 invalidStrings.forEach((arg) => {