diff --git a/samples/net/gptp/boards/native_posix.conf b/samples/net/gptp/boards/native_posix.conf
index d0d3b870c45..c514520186c 100644
--- a/samples/net/gptp/boards/native_posix.conf
+++ b/samples/net/gptp/boards/native_posix.conf
@@ -3,3 +3,6 @@ CONFIG_ETH_NATIVE_POSIX_PTP_CLOCK=y
 
 #CONFIG_ETH_NATIVE_POSIX_RANDOM_MAC=y
 CONFIG_ETH_NATIVE_POSIX_MAC_ADDR="00:00:5e:00:53:2a"
+
+# Assume 1 ms accuracy for native_posix simulated clock
+CONFIG_NET_GPTP_CLOCK_ACCURACY_1MS=y
diff --git a/samples/net/gptp/boards/native_posix_64.conf b/samples/net/gptp/boards/native_posix_64.conf
index d0d3b870c45..c514520186c 100644
--- a/samples/net/gptp/boards/native_posix_64.conf
+++ b/samples/net/gptp/boards/native_posix_64.conf
@@ -3,3 +3,6 @@ CONFIG_ETH_NATIVE_POSIX_PTP_CLOCK=y
 
 #CONFIG_ETH_NATIVE_POSIX_RANDOM_MAC=y
 CONFIG_ETH_NATIVE_POSIX_MAC_ADDR="00:00:5e:00:53:2a"
+
+# Assume 1 ms accuracy for native_posix simulated clock
+CONFIG_NET_GPTP_CLOCK_ACCURACY_1MS=y