diff --git a/THIRD_PARTY_NOTICES.md b/THIRD_PARTY_NOTICES.md
index 5a48d567fac..8931402f98e 100644
--- a/THIRD_PARTY_NOTICES.md
+++ b/THIRD_PARTY_NOTICES.md
@@ -62,6 +62,22 @@ limitations under the License.
 
 ---
 
+## Howard Hinnant — Date Algorithms (Public Domain)
+
+**Source:** https://howardhinnant.github.io/date_algorithms.html<br>
+**License:** Public Domain<br>
+**Copyright:** None; public domain dedication by Howard Hinnant
+
+### Scope
+
+The Sentry Java SDK includes adapted civil date conversion algorithms from Howard Hinnant's date algorithms for UTC ISO 8601 timestamp parsing and formatting. The code resides in `io.sentry.vendor.SentryIso8601Utils`.
+
+```
+Consider these donated to the public domain.
+```
+
+---
+
 ## Android Open Source Project — Base64 (Apache 2.0)
 
 **Source:** https://cs.android.com/android/platform/superproject/main/+/main:frameworks/base/core/java/android/util/Base64.java<br>
diff --git a/sentry/api/sentry.api b/sentry/api/sentry.api
index 45268a9a894..df043e92e1c 100644
--- a/sentry/api/sentry.api
+++ b/sentry/api/sentry.api
@@ -8076,6 +8076,11 @@ public class io/sentry/vendor/Base64 {
 	public static fun encodeToString ([BIII)Ljava/lang/String;
 }
 
+public final class io/sentry/vendor/SentryIso8601Utils {
+	public static fun formatTimestamp (J)Ljava/lang/String;
+	public static fun parseTimestamp (Ljava/lang/String;)J
+}
+
 public class io/sentry/vendor/gson/internal/bind/util/ISO8601Utils {
 	public static final field TIMEZONE_UTC Ljava/util/TimeZone;
 	public fun <init> ()V
diff --git a/sentry/src/main/java/io/sentry/Breadcrumb.java b/sentry/src/main/java/io/sentry/Breadcrumb.java
index d122d1459bf..c45b15b4711 100644
--- a/sentry/src/main/java/io/sentry/Breadcrumb.java
+++ b/sentry/src/main/java/io/sentry/Breadcrumb.java
@@ -823,7 +823,12 @@ public static final class JsonKeys {
   public void serialize(final @NotNull ObjectWriter writer, final @NotNull ILogger logger)
       throws IOException {
     writer.beginObject();
-    writer.name(JsonKeys.TIMESTAMP).value(logger, getTimestamp());
+    writer
+        .name(JsonKeys.TIMESTAMP)
+        .value(
+            timestampMs != null
+                ? DateUtils.getTimestampFromMillis(timestampMs)
+                : DateUtils.getTimestamp(getTimestamp()));
     if (message != null) {
       writer.name(JsonKeys.MESSAGE).value(message);
     }
diff --git a/sentry/src/main/java/io/sentry/DateUtils.java b/sentry/src/main/java/io/sentry/DateUtils.java
index 31a8dcd76ea..3fae5cf8264 100644
--- a/sentry/src/main/java/io/sentry/DateUtils.java
+++ b/sentry/src/main/java/io/sentry/DateUtils.java
@@ -2,11 +2,9 @@
 
 import static io.sentry.vendor.gson.internal.bind.util.ISO8601Utils.TIMEZONE_UTC;
 
-import io.sentry.vendor.gson.internal.bind.util.ISO8601Utils;
+import io.sentry.vendor.SentryIso8601Utils;
 import java.math.BigDecimal;
 import java.math.RoundingMode;
-import java.text.ParseException;
-import java.text.ParsePosition;
 import java.util.Calendar;
 import java.util.Date;
 import org.jetbrains.annotations.ApiStatus;
@@ -15,6 +13,7 @@
 
 /** Utilities to deal with dates */
 @ApiStatus.Internal
+@SuppressWarnings("JavaUtilDate")
 public final class DateUtils {
 
   private DateUtils() {}
@@ -39,8 +38,8 @@ private DateUtils() {}
   public static @NotNull Date getDateTime(final @NotNull String timestamp)
       throws IllegalArgumentException {
     try {
-      return ISO8601Utils.parse(timestamp, new ParsePosition(0));
-    } catch (ParseException e) {
+      return getDateTime(SentryIso8601Utils.parseTimestamp(timestamp));
+    } catch (IllegalArgumentException e) {
       throw new IllegalArgumentException("timestamp is not ISO format " + timestamp);
     }
   }
@@ -51,7 +50,6 @@ private DateUtils() {}
    * @param timestamp millis eg 1581410911.988 (1581410911 seconds and 988 millis)
    * @return the UTC Date
    */
-  @SuppressWarnings("JdkObsolete")
   public static @NotNull Date getDateTimeWithMillisPrecision(final @NotNull String timestamp)
       throws IllegalArgumentException {
     try {
@@ -69,7 +67,17 @@ private DateUtils() {}
    * @return the UTC/ISO 8601 timestamp
    */
   public static @NotNull String getTimestamp(final @NotNull Date date) {
-    return ISO8601Utils.format(date, true);
+    return getTimestampFromMillis(date.getTime());
+  }
+
+  /**
+   * Get the UTC/ISO 8601 timestamp from millis.
+   *
+   * @param millis the UTC millis from the epoch
+   * @return the UTC/ISO 8601 timestamp
+   */
+  static @NotNull String getTimestampFromMillis(final long millis) {
+    return SentryIso8601Utils.formatTimestamp(millis);
   }
 
   /**
diff --git a/sentry/src/main/java/io/sentry/vendor/SentryIso8601Utils.java b/sentry/src/main/java/io/sentry/vendor/SentryIso8601Utils.java
new file mode 100644
index 00000000000..66fdc34e80b
--- /dev/null
+++ b/sentry/src/main/java/io/sentry/vendor/SentryIso8601Utils.java
@@ -0,0 +1,282 @@
+// Civil date conversion algorithms adapted from Howard Hinnant's date algorithms.
+// Placed in the public domain by Howard Hinnant.
+// https://howardhinnant.github.io/date_algorithms.html
+
+package io.sentry.vendor;
+
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+
+@ApiStatus.Internal
+public final class SentryIso8601Utils {
+
+  private static final long MILLIS_PER_SECOND = 1000L;
+  private static final long MILLIS_PER_MINUTE = 60L * MILLIS_PER_SECOND;
+  private static final long MILLIS_PER_HOUR = 60L * MILLIS_PER_MINUTE;
+  private static final long MILLIS_PER_DAY = 24L * MILLIS_PER_HOUR;
+  private static final int DAYS_0000_TO_1970 = 719468;
+
+  private SentryIso8601Utils() {}
+
+  public static long parseTimestamp(final @NotNull String timestamp) {
+    final int length = timestamp.length();
+    int offset = 0;
+
+    final int year = parseInt(timestamp, offset, offset += 4);
+    if (checkOffset(timestamp, offset, '-')) {
+      offset++;
+    }
+
+    final int month = parseInt(timestamp, offset, offset += 2);
+    if (checkOffset(timestamp, offset, '-')) {
+      offset++;
+    }
+
+    final int day = parseInt(timestamp, offset, offset += 2);
+    validateDate(year, month, day);
+
+    if (!checkOffset(timestamp, offset, 'T')) {
+      if (offset != length) {
+        throw new IllegalArgumentException("Invalid date separator");
+      }
+      return epochMillis(year, month, day, 0, 0, 0, 0, 0);
+    }
+    offset++;
+
+    final int hour = parseInt(timestamp, offset, offset += 2);
+    if (checkOffset(timestamp, offset, ':')) {
+      offset++;
+    }
+
+    final int minute = parseInt(timestamp, offset, offset += 2);
+    if (checkOffset(timestamp, offset, ':')) {
+      offset++;
+    }
+
+    int second = 0;
+    int millisecond = 0;
+    if (length > offset) {
+      final char c = timestamp.charAt(offset);
+      if (c != 'Z' && c != '+' && c != '-') {
+        second = parseInt(timestamp, offset, offset += 2);
+        if (second > 59 && second < 63) {
+          second = 59;
+        }
+        if (checkOffset(timestamp, offset, '.')) {
+          offset++;
+          final int endOffset = indexOfNonDigit(timestamp, offset);
+          if (endOffset == offset) {
+            throw new IllegalArgumentException("Missing millisecond digits");
+          }
+          final int parseEndOffset = Math.min(endOffset, offset + 3);
+          final int fraction = parseInt(timestamp, offset, parseEndOffset);
+          switch (parseEndOffset - offset) {
+            case 1:
+              millisecond = fraction * 100;
+              break;
+            case 2:
+              millisecond = fraction * 10;
+              break;
+            default:
+              millisecond = fraction;
+              break;
+          }
+          offset = endOffset;
+        }
+      }
+    }
+    validateTime(hour, minute, second, millisecond);
+
+    if (length <= offset) {
+      throw new IllegalArgumentException("No time zone indicator");
+    }
+
+    final int timezoneOffsetMillis;
+    final char timezoneIndicator = timestamp.charAt(offset);
+    if (timezoneIndicator == 'Z') {
+      timezoneOffsetMillis = 0;
+      offset++;
+    } else if (timezoneIndicator == '+' || timezoneIndicator == '-') {
+      final int sign = timezoneIndicator == '+' ? 1 : -1;
+      offset++;
+      final int timezoneHour = parseInt(timestamp, offset, offset += 2);
+      int timezoneMinute = 0;
+      if (checkOffset(timestamp, offset, ':')) {
+        offset++;
+      }
+      if (length >= offset + 2) {
+        timezoneMinute = parseInt(timestamp, offset, offset += 2);
+      }
+      validateTimezone(timezoneHour, timezoneMinute);
+      timezoneOffsetMillis =
+          sign * (int) (timezoneHour * MILLIS_PER_HOUR + timezoneMinute * MILLIS_PER_MINUTE);
+    } else {
+      throw new IllegalArgumentException("Invalid time zone indicator");
+    }
+
+    if (offset != length) {
+      throw new IllegalArgumentException("Invalid trailing characters");
+    }
+
+    return epochMillis(year, month, day, hour, minute, second, millisecond, timezoneOffsetMillis);
+  }
+
+  public static @NotNull String formatTimestamp(final long millis) {
+    final long epochDay = Math.floorDiv(millis, MILLIS_PER_DAY);
+    int millisOfDay = (int) Math.floorMod(millis, MILLIS_PER_DAY);
+
+    final int[] yearMonthDay = epochDayToYearMonthDay(epochDay);
+    final int hour = millisOfDay / (int) MILLIS_PER_HOUR;
+    millisOfDay -= hour * (int) MILLIS_PER_HOUR;
+    final int minute = millisOfDay / (int) MILLIS_PER_MINUTE;
+    millisOfDay -= minute * (int) MILLIS_PER_MINUTE;
+    final int second = millisOfDay / (int) MILLIS_PER_SECOND;
+    final int millisecond = millisOfDay - second * (int) MILLIS_PER_SECOND;
+
+    final StringBuilder timestamp = new StringBuilder("yyyy-MM-ddThh:mm:ss.sssZ".length());
+    padInt(timestamp, yearMonthDay[0], "yyyy".length());
+    timestamp.append('-');
+    padInt(timestamp, yearMonthDay[1], "MM".length());
+    timestamp.append('-');
+    padInt(timestamp, yearMonthDay[2], "dd".length());
+    timestamp.append('T');
+    padInt(timestamp, hour, "hh".length());
+    timestamp.append(':');
+    padInt(timestamp, minute, "mm".length());
+    timestamp.append(':');
+    padInt(timestamp, second, "ss".length());
+    timestamp.append('.');
+    padInt(timestamp, millisecond, "sss".length());
+    timestamp.append('Z');
+    return timestamp.toString();
+  }
+
+  private static long epochMillis(
+      final int year,
+      final int month,
+      final int day,
+      final int hour,
+      final int minute,
+      final int second,
+      final int millisecond,
+      final int timezoneOffsetMillis) {
+    return daysFromYearMonthDay(year, month, day) * MILLIS_PER_DAY
+        + hour * MILLIS_PER_HOUR
+        + minute * MILLIS_PER_MINUTE
+        + second * MILLIS_PER_SECOND
+        + millisecond
+        - timezoneOffsetMillis;
+  }
+
+  private static long daysFromYearMonthDay(int year, final int month, final int day) {
+    year -= month <= 2 ? 1 : 0;
+    final long era = Math.floorDiv(year, 400);
+    final int yearOfEra = (int) (year - era * 400);
+    final int dayOfYear = (153 * (month + (month > 2 ? -3 : 9)) + 2) / 5 + day - 1;
+    final int dayOfEra = yearOfEra * 365 + yearOfEra / 4 - yearOfEra / 100 + dayOfYear;
+    return era * 146097 + dayOfEra - DAYS_0000_TO_1970;
+  }
+
+  private static int[] epochDayToYearMonthDay(long epochDay) {
+    epochDay += DAYS_0000_TO_1970;
+    final long era = Math.floorDiv(epochDay, 146097);
+    final int dayOfEra = (int) (epochDay - era * 146097);
+    final int yearOfEra = (dayOfEra - dayOfEra / 1460 + dayOfEra / 36524 - dayOfEra / 146096) / 365;
+    final int year = (int) (yearOfEra + era * 400);
+    final int dayOfYear = dayOfEra - (365 * yearOfEra + yearOfEra / 4 - yearOfEra / 100);
+    final int monthPrime = (5 * dayOfYear + 2) / 153;
+    final int day = dayOfYear - (153 * monthPrime + 2) / 5 + 1;
+    final int month = monthPrime < 10 ? monthPrime + 3 : monthPrime - 9;
+    return new int[] {year + (month <= 2 ? 1 : 0), month, day};
+  }
+
+  private static void validateDate(final int year, final int month, final int day) {
+    if (year < 1 || month < 1 || month > 12 || day < 1 || day > daysInMonth(year, month)) {
+      throw new IllegalArgumentException("Invalid date");
+    }
+  }
+
+  private static void validateTime(
+      final int hour, final int minute, final int second, final int millisecond) {
+    if (hour < 0
+        || hour > 23
+        || minute < 0
+        || minute > 59
+        || second < 0
+        || second > 59
+        || millisecond < 0
+        || millisecond > 999) {
+      throw new IllegalArgumentException("Invalid time");
+    }
+  }
+
+  private static void validateTimezone(final int hour, final int minute) {
+    if (hour < 0 || hour > 23 || minute < 0 || minute > 59) {
+      throw new IllegalArgumentException("Invalid time zone");
+    }
+  }
+
+  private static int daysInMonth(final int year, final int month) {
+    switch (month) {
+      case 2:
+        return isLeapYear(year) ? 29 : 28;
+      case 4:
+      case 6:
+      case 9:
+      case 11:
+        return 30;
+      default:
+        return 31;
+    }
+  }
+
+  private static boolean isLeapYear(final int year) {
+    return (year % 4 == 0) && (year % 100 != 0 || year % 400 == 0);
+  }
+
+  private static boolean checkOffset(
+      final @NotNull String value, final int offset, final char expected) {
+    return offset < value.length() && value.charAt(offset) == expected;
+  }
+
+  private static int parseInt(
+      final @NotNull String value, final int beginIndex, final int endIndex) {
+    if (beginIndex < 0 || endIndex > value.length() || beginIndex >= endIndex) {
+      throw new NumberFormatException(value);
+    }
+
+    int result = 0;
+    for (int i = beginIndex; i < endIndex; i++) {
+      final char c = value.charAt(i);
+      if (c < '0' || c > '9') {
+        throw new NumberFormatException("Invalid number: " + value.substring(beginIndex, endIndex));
+      }
+      result = result * 10 + c - '0';
+    }
+    return result;
+  }
+
+  private static void padInt(
+      final @NotNull StringBuilder buffer, final int value, final int length) {
+    if (value < 0) {
+      buffer.append('-');
+      padInt(buffer, -value, length);
+      return;
+    }
+    final String strValue = Integer.toString(value);
+    for (int i = length - strValue.length(); i > 0; i--) {
+      buffer.append('0');
+    }
+    buffer.append(strValue);
+  }
+
+  private static int indexOfNonDigit(final @NotNull String string, final int offset) {
+    for (int i = offset; i < string.length(); i++) {
+      final char c = string.charAt(i);
+      if (c < '0' || c > '9') {
+        return i;
+      }
+    }
+    return string.length();
+  }
+}
diff --git a/sentry/src/test/java/io/sentry/DateUtilsTest.kt b/sentry/src/test/java/io/sentry/DateUtilsTest.kt
index 9e234b50c1b..0746b1a1b5f 100644
--- a/sentry/src/test/java/io/sentry/DateUtilsTest.kt
+++ b/sentry/src/test/java/io/sentry/DateUtilsTest.kt
@@ -7,6 +7,7 @@ import java.time.format.DateTimeFormatter
 import java.util.Date
 import kotlin.test.Test
 import kotlin.test.assertEquals
+import kotlin.test.assertFailsWith
 import kotlin.test.assertNotNull
 import kotlin.test.assertTrue
 
@@ -34,6 +35,54 @@ class DateUtilsTest {
     assertEquals("2020-03-27T08:52:58.000Z", timestamp)
   }
 
+  @Test
+  fun `When ISO date has offset`() {
+    val input =
+      mapOf(
+        "2020-03-27T10:52:58.015+02:00" to "2020-03-27T08:52:58.015Z",
+        "2020-03-27T10:52:58.015+0200" to "2020-03-27T08:52:58.015Z",
+        "2020-03-27T10:52:58.015+02" to "2020-03-27T08:52:58.015Z",
+        "2020-03-27T05:52:58.015-03:00" to "2020-03-27T08:52:58.015Z",
+      )
+
+    input.forEach {
+      val timestamp = convertDate(DateUtils.getDateTime(it.key)).format(isoFormat)
+
+      assertEquals(it.value, timestamp)
+    }
+  }
+
+  @Test
+  fun `When ISO date uses compact separators`() {
+    val date = DateUtils.getDateTime("20200327T085258.015Z")
+
+    val utcDate = convertDate(date)
+    val timestamp = utcDate.format(isoFormat)
+
+    assertEquals("2020-03-27T08:52:58.015Z", timestamp)
+  }
+
+  @Test
+  fun `When ISO date has short fraction`() {
+    val input =
+      mapOf(
+        "2020-03-27T08:52:58.1Z" to "2020-03-27T08:52:58.100Z",
+        "2020-03-27T08:52:58.12Z" to "2020-03-27T08:52:58.120Z",
+        "2020-03-27T08:52:58.123456Z" to "2020-03-27T08:52:58.123Z",
+      )
+
+    input.forEach {
+      val timestamp = convertDate(DateUtils.getDateTime(it.key)).format(isoFormat)
+
+      assertEquals(it.value, timestamp)
+    }
+  }
+
+  @Test
+  fun `When ISO date is invalid`() {
+    assertFailsWith<IllegalArgumentException> { DateUtils.getDateTime("2020-02-30T08:52:58Z") }
+  }
+
   @Test
   fun `Converts from Date to ISO 8601 and back to Date`() {
     val currentDate = DateUtils.getCurrentDateTime()
@@ -78,6 +127,21 @@ class DateUtilsTest {
     assertTrue { utcCurrentDate.minusSeconds(1).isBefore(utcDate) }
   }
 
+  @Test
+  fun `Formats millis to ISO 8601 timestamp`() {
+    val input =
+      mapOf(
+        Instant.parse("1970-01-01T00:00:00.000Z").toEpochMilli() to "1970-01-01T00:00:00.000Z",
+        Instant.parse("1969-12-31T23:59:59.999Z").toEpochMilli() to "1969-12-31T23:59:59.999Z",
+        Instant.parse("2000-02-29T12:34:56.789Z").toEpochMilli() to "2000-02-29T12:34:56.789Z",
+        Instant.parse("1900-03-01T00:00:00.000Z").toEpochMilli() to "1900-03-01T00:00:00.000Z",
+        Instant.parse("2100-03-01T00:00:00.000Z").toEpochMilli() to "2100-03-01T00:00:00.000Z",
+        Instant.parse("2400-02-29T23:59:59.999Z").toEpochMilli() to "2400-02-29T23:59:59.999Z",
+      )
+
+    input.forEach { assertEquals(it.value, DateUtils.getTimestampFromMillis(it.key)) }
+  }
+
   @Test
   fun `Millis formats to Date`() {
     val millis = 1591533492L * 1000L + 631
@@ -86,6 +150,7 @@ class DateUtilsTest {
     val utcActual = convertDate(actual)
     val timestamp = utcActual.format(isoFormat)
 
+    assertEquals(millis, actual.time)
     assertEquals("2020-06-07T12:38:12.631Z", timestamp)
   }