diff --git a/drivers/include/periph/rtc.h b/drivers/include/periph/rtc.h
index 9a424fecc7..0071711999 100644
--- a/drivers/include/periph/rtc.h
+++ b/drivers/include/periph/rtc.h
@@ -90,6 +90,19 @@ int rtc_set_time(struct tm *time);
  */
 int rtc_get_time(struct tm *time);
 
+/**
+ * @brief Get current RTC time with sub-second component.
+ *        Requires the `periph_rtc_ms` feature.
+ *
+ * @param[out] time         Pointer to the struct to write the time to.
+ * @param[out] ms           Pointer to a variable to hold the microsecond
+ *                          component of the current RTC time.
+ *
+ * @return  0 for success
+ * @return -1 an error occurred
+ */
+int rtc_get_time_ms(struct tm *time, uint16_t *ms);
+
 /**
  * @brief Set an alarm for RTC to the specified value.
  *
diff --git a/drivers/rtt_rtc/Makefile.features b/drivers/rtt_rtc/Makefile.features
new file mode 100644
index 0000000000..1ed82b05fe
--- /dev/null
+++ b/drivers/rtt_rtc/Makefile.features
@@ -0,0 +1,2 @@
+FEATURES_PROVIDED += periph_rtc
+FEATURES_PROVIDED += periph_rtc_ms
diff --git a/drivers/rtt_rtc/rtt_rtc.c b/drivers/rtt_rtc/rtt_rtc.c
index 878bc6ea94..2e16ac69c6 100644
--- a/drivers/rtt_rtc/rtt_rtc.c
+++ b/drivers/rtt_rtc/rtt_rtc.c
@@ -28,6 +28,7 @@
 
 #include "periph/rtc.h"
 #include "periph/rtt.h"
+#include "timex.h"
 
 #define ENABLE_DEBUG    0
 #include "debug.h"
@@ -40,6 +41,7 @@
 
 #define TICKS(x)        (    (x) * RTT_SECOND)
 #define SECONDS(x)      (_RTT(x) / RTT_SECOND)
+#define SUBSECONDS(x)   (_RTT(x) % RTT_SECOND)
 
 /* Place counter in .noinit section if no backup RAM is available.
    This means the date is undefined at cold boot, but will likely still
@@ -133,6 +135,22 @@ int rtc_set_time(struct tm *time)
     return 0;
 }
 
+int rtc_get_time_ms(struct tm *time, uint16_t *ms)
+{
+    uint32_t prev = rtc_now;
+
+    /* repeat calculation if an alarm triggered in between */
+    do {
+        uint32_t now = rtt_get_counter();
+        uint32_t tmp = _rtc_now(now);
+
+        rtc_localtime(tmp, time);
+        *ms = (SUBSECONDS(now) * MS_PER_SEC) / RTT_SECOND;
+    } while (prev != rtc_now);
+
+    return 0;
+}
+
 int rtc_get_time(struct tm *time)
 {
     uint32_t prev = rtc_now;