diff --git a/gson/src/main/java/com/google/gson/internal/bind/util/ISO8601Utils.java b/gson/src/main/java/com/google/gson/internal/bind/util/ISO8601Utils.java
index 606d6c7146..2bf1aa84a1 100644
--- a/gson/src/main/java/com/google/gson/internal/bind/util/ISO8601Utils.java
+++ b/gson/src/main/java/com/google/gson/internal/bind/util/ISO8601Utils.java
@@ -239,12 +239,12 @@ public static Date parse(String date, ParsePosition pos) throws ParseException {
         offset += 1;
       } else if (timezoneIndicator == '+' || timezoneIndicator == '-') {
         String timezoneOffset = date.substring(offset);
+        offset += timezoneOffset.length();
 
         // When timezone has no minutes, we should append it, valid timezones are, for example:
         // +00:00, +0000 and +00
         timezoneOffset = timezoneOffset.length() >= 5 ? timezoneOffset : timezoneOffset + "00";
 
-        offset += timezoneOffset.length();
         // 18-Jun-2015, tatu: Minor simplification, skip offset of "+0000"/"+00:00"
         if (timezoneOffset.equals("+0000") || timezoneOffset.equals("+00:00")) {
           timezone = TIMEZONE_UTC;
diff --git a/gson/src/test/java/com/google/gson/internal/bind/util/ISO8601UtilsTest.java b/gson/src/test/java/com/google/gson/internal/bind/util/ISO8601UtilsTest.java
index 1c2d254dec..f2d11b5ef0 100644
--- a/gson/src/test/java/com/google/gson/internal/bind/util/ISO8601UtilsTest.java
+++ b/gson/src/test/java/com/google/gson/internal/bind/util/ISO8601UtilsTest.java
@@ -107,6 +107,30 @@ public void testDateParseWithTimezone() throws ParseException {
     assertThat(date).isEqualTo(expectedDate);
   }
 
+  @Test
+  @SuppressWarnings("JavaUtilDate")
+  public void testDateParseShortTimezonePosition() throws ParseException {
+    for (String timezone : new String[] {"+00", "+01", "-02", "+01:30", "+0130"}) {
+      String dateStr = "2018-06-25T00:00:00" + timezone;
+      ParsePosition position = new ParsePosition(0);
+      Date date = ISO8601Utils.parse(dateStr, position);
+      assertThat(position.getIndex()).isEqualTo(dateStr.length());
+
+      String fullTimezone = timezone.length() == 3 ? timezone + ":00" : timezone;
+      Date expected =
+          ISO8601Utils.parse("2018-06-25T00:00:00" + fullTimezone, new ParsePosition(0));
+      assertThat(date.getTime()).isEqualTo(expected.getTime());
+    }
+  }
+
+  @Test
+  public void testDateParseShortTimezoneFromNonzeroPosition() throws ParseException {
+    String dateStr = "prefix 2018-06-25T00:00:00+01";
+    ParsePosition position = new ParsePosition("prefix ".length());
+    ISO8601Utils.parse(dateStr, position);
+    assertThat(position.getIndex()).isEqualTo(dateStr.length());
+  }
+
   @Test
   @SuppressWarnings("UndefinedEquals")
   public void testDateParseSpecialTimezone() throws ParseException {