diff --git a/CHANGELOG.md b/CHANGELOG.md
index a46d6ef3e..0a3e5aece 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@ SPDX-License-Identifier: GPL-3.0-or-later
 ### Changed
 
 - api: add support of date like ISO 8601 but with spaces and lower `t` and `z` in function util_parse_time
+- logger: change default time format to "%@%F %T.%fZ" (UTC)
 - logger: use function util_parse_time to parse date/time in log files
 - build: require Curl ≥ 7.68.0 ([#2268](https://github.com/weechat/weechat/issues/2268))
 - build: require GnuTLS ≥ 3.6.3 ([#2268](https://github.com/weechat/weechat/issues/2268))
diff --git a/src/plugins/logger/logger-config.c b/src/plugins/logger/logger-config.c
index 7140257ce..221cbd5a3 100644
--- a/src/plugins/logger/logger-config.c
+++ b/src/plugins/logger/logger-config.c
@@ -718,7 +718,7 @@ logger_config_init (void)
             N_("timestamp used in log files (see man strftime for date/time "
                "specifiers, extra specifiers are supported, see function "
                "util_strftimeval in Plugin API reference)"),
-            NULL, 0, 0, "%Y-%m-%d %H:%M:%S", NULL, 0,
+            NULL, 0, 0, "%@%F %T.%fZ", NULL, 0,
             NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
     }
 
diff --git a/tests/unit/plugins/logger/test-logger-backlog.cpp b/tests/unit/plugins/logger/test-logger-backlog.cpp
index 410fef124..06288599c 100644
--- a/tests/unit/plugins/logger/test-logger-backlog.cpp
+++ b/tests/unit/plugins/logger/test-logger-backlog.cpp
@@ -103,7 +103,7 @@ TEST(LoggerBacklog, DisplayLine)
 
     /* valid line */
     snprintf (str_line, sizeof (str_line),
-              "2022-02-19 16:32:20\tnick\tthe message");
+              "2022-02-19 16:32:20.123456Z\tnick\tthe message");
     logger_backlog_display_line (gui_buffers, str_line);
     ptr_data = gui_buffers->own_lines->last_line->data;
     LONGS_EQUAL(1645288340, ptr_data->date);
@@ -127,7 +127,7 @@ TEST(LoggerBacklog, DisplayLine)
 
     /* valid line with Tab in message */
     snprintf (str_line, sizeof (str_line),
-              "2022-02-19 16:32:21\tnick\tthe message\twith tab");
+              "2022-02-19 16:32:21.123456Z\tnick\tthe message\twith tab");
     logger_backlog_display_line (gui_buffers, str_line);
     ptr_data = gui_buffers->own_lines->last_line->data;
     LONGS_EQUAL(1645288341, ptr_data->date);
@@ -193,19 +193,19 @@ TEST(LoggerBacklog, GroupMessages)
 {
     struct t_arraylist *lines, *messages;
     const char *test_lines_1[] = {
-        "2023-06-04 21:15:34\t\tMessage 1",
-        "2023-06-04 21:15:40\t\tMessage 2",
+        "2023-06-04 21:15:34.123456Z\t\tMessage 1",
+        "2023-06-04 21:15:40.123456Z\t\tMessage 2",
         NULL,
     };
     const char *test_lines_2[] = {
         "end of line",
-        "2023-06-04 21:15:34\t\tFirst line",
+        "2023-06-04 21:15:34.123456Z\t\tFirst line",
         "of multiline message",
         "",
         "end of message",
-        "2023-06-04 21:15:37\t\tTwo lines with empty line",
+        "2023-06-04 21:15:37.123456Z\t\tTwo lines with empty line",
         "",
-        "2023-06-04 21:15:40\t\tMessage on one line",
+        "2023-06-04 21:15:40.123456Z\t\tMessage on one line",
         NULL,
     };
     int i;
@@ -224,9 +224,9 @@ TEST(LoggerBacklog, GroupMessages)
     messages = logger_backlog_group_messages (lines);
     CHECK(messages);
     LONGS_EQUAL(2, arraylist_size (messages));
-    STRCMP_EQUAL("2023-06-04 21:15:34\t\tMessage 1",
+    STRCMP_EQUAL("2023-06-04 21:15:34.123456Z\t\tMessage 1",
                  (const char *)arraylist_get (messages, 0));
-    STRCMP_EQUAL("2023-06-04 21:15:40\t\tMessage 2",
+    STRCMP_EQUAL("2023-06-04 21:15:40.123456Z\t\tMessage 2",
                  (const char *)arraylist_get (messages, 1));
     arraylist_free (messages);
 
@@ -242,14 +242,14 @@ TEST(LoggerBacklog, GroupMessages)
     LONGS_EQUAL(4, arraylist_size (messages));
     STRCMP_EQUAL("end of line",
                  (const char *)arraylist_get (messages, 0));
-    STRCMP_EQUAL("2023-06-04 21:15:34\t\tFirst line\n"
+    STRCMP_EQUAL("2023-06-04 21:15:34.123456Z\t\tFirst line\n"
                  "of multiline message\n"
                  "\n"
                  "end of message",
                  (const char *)arraylist_get (messages, 1));
-    STRCMP_EQUAL("2023-06-04 21:15:37\t\tTwo lines with empty line\n",
+    STRCMP_EQUAL("2023-06-04 21:15:37.123456Z\t\tTwo lines with empty line\n",
                  (const char *)arraylist_get (messages, 2));
-    STRCMP_EQUAL("2023-06-04 21:15:40\t\tMessage on one line",
+    STRCMP_EQUAL("2023-06-04 21:15:40.123456Z\t\tMessage on one line",
                  (const char *)arraylist_get (messages, 3));
     arraylist_free (messages);