diff --git a/tests/unit/timeutil/main.c b/tests/unit/timeutil/main.c
index d6e6573d77c..79d6e007c5d 100644
--- a/tests/unit/timeutil/main.c
+++ b/tests/unit/timeutil/main.c
@@ -52,14 +52,4 @@ void timeutil_check(const struct timeutil_test_data *tp,
 	}
 }
 
-/*test case main entry*/
-void test_main(void)
-{
-	ztest_test_suite(test_timeutil_api,
-			 ztest_unit_test(test_gmtime),
-			 ztest_unit_test(test_s32),
-			 ztest_unit_test(test_s64),
-			 ztest_unit_test(test_sync)
-			 );
-	ztest_run_test_suite(test_timeutil_api);
-}
+ZTEST_SUITE(timeutil_api, NULL, NULL, NULL, NULL, NULL);
diff --git a/tests/unit/timeutil/prj.conf b/tests/unit/timeutil/prj.conf
new file mode 100644
index 00000000000..963087265ce
--- /dev/null
+++ b/tests/unit/timeutil/prj.conf
@@ -0,0 +1 @@
+CONFIG_ZTEST_NEW_API=y
diff --git a/tests/unit/timeutil/test_gmtime.c b/tests/unit/timeutil/test_gmtime.c
index 5daa1aa2206..0bea06ede49 100644
--- a/tests/unit/timeutil/test_gmtime.c
+++ b/tests/unit/timeutil/test_gmtime.c
@@ -10,7 +10,7 @@
 #include <zephyr/ztest.h>
 #include "timeutil_test.h"
 
-void test_gmtime(void)
+ZTEST(timeutil_api, test_gmtime)
 {
 	struct tm tm = {
 		/* Initialize an unset field */
diff --git a/tests/unit/timeutil/test_s32.c b/tests/unit/timeutil/test_s32.c
index b28fb28eba5..b4a4c65f1f4 100644
--- a/tests/unit/timeutil/test_s32.c
+++ b/tests/unit/timeutil/test_s32.c
@@ -238,7 +238,7 @@ static const struct timeutil_test_data tests[] = {
 	  } },
 };
 
-void test_s32(void)
+ZTEST(timeutil_api, test_s32)
 {
 	timeutil_check(tests, sizeof(tests) / sizeof(*tests));
 }
diff --git a/tests/unit/timeutil/test_s64.c b/tests/unit/timeutil/test_s64.c
index 94c339b015e..44484636c90 100644
--- a/tests/unit/timeutil/test_s64.c
+++ b/tests/unit/timeutil/test_s64.c
@@ -323,7 +323,7 @@ static void test_time32_overflow(void)
 		      "final errno state bad");
 }
 
-void test_s64(void)
+ZTEST(timeutil_api, test_s64)
 {
 	if (sizeof(time_t) < 8U) {
 		test_time32_errno_clear();
diff --git a/tests/unit/timeutil/test_sync.c b/tests/unit/timeutil/test_sync.c
index bf43d9c4ede..4e31f1acfba 100644
--- a/tests/unit/timeutil/test_sync.c
+++ b/tests/unit/timeutil/test_sync.c
@@ -426,7 +426,7 @@ static void test_skew_to_ppb(void)
 		      "unexpected above limit: %.10g %d", skew, ppb);
 }
 
-void test_sync(void)
+ZTEST(timeutil_api, test_sync)
 {
 	test_state_update();
 	test_state_set_skew();