diff --git a/src/Forms/DateField.php b/src/Forms/DateField.php
index 880fa0827..83a695c4b 100644
--- a/src/Forms/DateField.php
+++ b/src/Forms/DateField.php
@@ -513,8 +513,8 @@ class DateField extends TextField
      * Convert frontend date to the internal representation (ISO 8601).
      * The frontend date is also in ISO 8601 when $html5=true.
      *
-     * @param string $date
-     * @return string The formatted date, or null if not a valid date
+     * @param ?string $date
+     * @return ?string The formatted date, or null if not a valid date
      */
     protected function frontendToInternal($date)
     {
@@ -524,6 +524,17 @@ class DateField extends TextField
         $fromFormatter = $this->getFrontendFormatter();
         $toFormatter = $this->getInternalFormatter();
         $timestamp = $fromFormatter->parse($date);
+
+        // Retry with expanded value
+        if ($timestamp === false) {
+            $zeroFormat = $fromFormatter->format(strtotime(date('Y-01-01 00:00:00')));
+            $expectedLength = strlen($zeroFormat);
+            if (strlen($date) < $expectedLength) {
+                $expandedValue = $date . substr($zeroFormat, strlen($date));
+                $timestamp = $fromFormatter->parse($expandedValue);
+            }
+        }
+        
         if ($timestamp === false) {
             return null;
         }
diff --git a/src/Forms/DatetimeField.php b/src/Forms/DatetimeField.php
index 849a0ecb8..2a52f1bfc 100644
--- a/src/Forms/DatetimeField.php
+++ b/src/Forms/DatetimeField.php
@@ -179,8 +179,8 @@ class DatetimeField extends TextField
      * Assumes the value is in the defined {@link $timezone} (if one is set),
      * and adjusts for server timezone.
      *
-     * @param string $datetime
-     * @return string The formatted date, or null if not a valid date
+     * @param ?string $datetime
+     * @return ?string The formatted date, or null if not a valid date
      */
     public function frontendToInternal($datetime)
     {
@@ -193,6 +193,16 @@ class DatetimeField extends TextField
         // Try to parse time with seconds
         $timestamp = $fromFormatter->parse($datetime);
 
+        // Retry with expanded value
+        if ($timestamp === false) {
+            $zeroFormat = $fromFormatter->format(strtotime(date('Y-01-01 00:00:00')));
+            $expectedLength = strlen($zeroFormat);
+            if (strlen($datetime) < $expectedLength) {
+                $expandedValue = $datetime . substr($zeroFormat, strlen($datetime));
+                $timestamp = $fromFormatter->parse($expandedValue);
+            }
+        }
+
         // Try to parse time without seconds, since that's a valid HTML5 submission format
         // See https://html.spec.whatwg.org/multipage/infrastructure.html#times
         if ($timestamp === false && $this->getHTML5()) {
diff --git a/src/Forms/TimeField.php b/src/Forms/TimeField.php
index 24ba4645f..41d86c65f 100644
--- a/src/Forms/TimeField.php
+++ b/src/Forms/TimeField.php
@@ -388,8 +388,8 @@ class TimeField extends TextField
      * Convert frontend time to the internal representation (ISO 8601).
      * The frontend time is also in ISO 8601 when $html5=true.
      *
-     * @param string $time
-     * @return string The formatted time, or null if not a valid time
+     * @param ?string $time
+     * @return ?string The formatted time, or null if not a valid time
      */
     protected function frontendToInternal($time)
     {
@@ -400,6 +400,16 @@ class TimeField extends TextField
         $toFormatter = $this->getInternalFormatter();
         $timestamp = $fromFormatter->parse($time);
 
+        // Retry with expanded value
+        if ($timestamp === false) {
+            $zeroFormat = $fromFormatter->format(strtotime(date('Y-01-01 00:00:00')));
+            $expectedLength = strlen($zeroFormat);
+            if (strlen($time) < $expectedLength) {
+                $expandedValue = $time . substr($zeroFormat, strlen($time));
+                $timestamp = $fromFormatter->parse($expandedValue);
+            }
+        }
+        
         // Try to parse time without seconds, since that's a valid HTML5 submission format
         // See https://html.spec.whatwg.org/multipage/infrastructure.html#times
         if ($timestamp === false && $this->getHTML5()) {