diff --git a/examples/platforms/simulation/logging.c b/examples/platforms/simulation/logging.c
index 8ac767771..e63eb44f5 100644
--- a/examples/platforms/simulation/logging.c
+++ b/examples/platforms/simulation/logging.c
@@ -90,6 +90,25 @@ void platformLoggingDeinit(void)
     }
 }
 
+#if OPENTHREAD_CONFIG_LOG_INSTANCE_AWARE_API_ENABLE
+
+void otPlatLogOutput(otInstance *aInstance, otLogLevel aLogLevel, const char *aLogLine)
+{
+    OT_UNUSED_VARIABLE(aInstance);
+    OT_UNUSED_VARIABLE(aLogLevel);
+
+    if (sLogFile == NULL)
+    {
+        syslog(LOG_CRIT, "[%lu] %s", (unsigned long)gNodeId, aLogLine);
+    }
+    else
+    {
+        fprintf(sLogFile, "%s\r\n", aLogLine);
+    }
+}
+
+#else
+
 void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat, ...)
 {
     OT_UNUSED_VARIABLE(aLogLevel);
@@ -118,9 +137,11 @@ void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat
     va_end(args);
 }
 
-#else
+#endif // OPENTHREAD_CONFIG_LOG_INSTANCE_AWARE_API_ENABLE
+
+#else // (OPENTHREAD_CONFIG_LOG_OUTPUT == OPENTHREAD_CONFIG_LOG_OUTPUT_PLATFORM_DEFINED)
 
 void platformLoggingInit(const char *aName) { OT_UNUSED_VARIABLE(aName); }
 void platformLoggingDeinit(void) {}
 
-#endif // (OPENTHREAD_CONFIG_LOG_OUTPUT == OPENTHREAD_CONFIG_LOG_OUTPUT_PLATFORM_DEFINED)
+#endif
diff --git a/examples/platforms/utils/debug_uart.c b/examples/platforms/utils/debug_uart.c
index 169c65dde..733df0b4e 100644
--- a/examples/platforms/utils/debug_uart.c
+++ b/examples/platforms/utils/debug_uart.c
@@ -120,6 +120,15 @@ otError otPlatDebugUart_logfile(const char *filename)
 }
 
 #if (OPENTHREAD_CONFIG_LOG_OUTPUT == OPENTHREAD_CONFIG_LOG_OUTPUT_DEBUG_UART)
+
+#if OPENTHREAD_CONFIG_LOG_INSTANCE_AWARE_API_ENABLE
+void otPlatLogOutput(otInstance *aInstance, otLogLevel aLogLevel, const char *aLogLine)
+{
+    OT_UNUSED_VARIABLE(aInstance);
+    otPlatLog(aLogLevel, OT_LOG_REGION_CORE, "%s", aLogLine);
+}
+#endif
+
 /* this should not be a WEAK function */
 void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat, ...)
 {
diff --git a/src/cli/cli_logging.cpp b/src/cli/cli_logging.cpp
index b788e454c..2933c7ba8 100644
--- a/src/cli/cli_logging.cpp
+++ b/src/cli/cli_logging.cpp
@@ -41,6 +41,14 @@
 
 #if OPENTHREAD_CONFIG_LOG_OUTPUT == OPENTHREAD_CONFIG_LOG_OUTPUT_APP
 
+#if OPENTHREAD_CONFIG_LOG_INSTANCE_AWARE_API_ENABLE
+extern "C" void otPlatLogOutput(otInstance *aInstance, otLogLevel aLogLevel, const char *aLogLine)
+{
+    OT_UNUSED_VARIABLE(aInstance);
+    otPlatLog(aLogLevel, OT_LOG_REGION_CORE, "%s", aLogLine);
+}
+#endif
+
 extern "C" OT_TOOL_WEAK void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat, ...)
 {
     va_list ap;
diff --git a/src/ncp/ncp_base.cpp b/src/ncp/ncp_base.cpp
index 798b057d0..9274bc2ba 100644
--- a/src/ncp/ncp_base.cpp
+++ b/src/ncp/ncp_base.cpp
@@ -2847,6 +2847,22 @@ otError otNcpStreamWrite(int aStreamId, const uint8_t *aDataPtr, int aDataLen)
 
 #if (OPENTHREAD_CONFIG_LOG_OUTPUT == OPENTHREAD_CONFIG_LOG_OUTPUT_APP)
 
+#if OPENTHREAD_CONFIG_LOG_INSTANCE_AWARE_API_ENABLE
+
+extern "C" void otPlatLogOutput(otInstance *aInstance, otLogLevel aLogLevel, const char *aLogLine)
+{
+    OT_UNUSED_VARIABLE(aInstance);
+
+    ot::Ncp::NcpBase *ncp = ot::Ncp::NcpBase::GetNcpInstance();
+
+    if (ncp != nullptr)
+    {
+        ncp->Log(aLogLevel, OT_LOG_REGION_CORE, aLogLine);
+    }
+}
+
+#else
+
 extern "C" void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat, ...)
 {
     va_list           args;
@@ -2866,4 +2882,6 @@ extern "C" void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const ch
     va_end(args);
 }
 
+#endif // OPENTHREAD_CONFIG_LOG_INSTANCE_AWARE_API_ENABLE
+
 #endif // (OPENTHREAD_CONFIG_LOG_OUTPUT == OPENTHREAD_CONFIG_LOG_OUTPUT_APP)
diff --git a/src/posix/platform/logging.cpp b/src/posix/platform/logging.cpp
index 8dd2a5b67..aac8bd123 100644
--- a/src/posix/platform/logging.cpp
+++ b/src/posix/platform/logging.cpp
@@ -36,40 +36,53 @@
 #include <openthread/platform/logging.h>
 
 #if OPENTHREAD_CONFIG_LOG_OUTPUT == OPENTHREAD_CONFIG_LOG_OUTPUT_PLATFORM_DEFINED
-OT_TOOL_WEAK void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat, ...)
-{
-    OT_UNUSED_VARIABLE(aLogRegion);
 
-    va_list args;
+static int ConvertLogLevelToSyslogLevel(otLogLevel aLogLevel)
+{
+    int level = LOG_DEBUG;
 
     switch (aLogLevel)
     {
     case OT_LOG_LEVEL_NONE:
-        aLogLevel = LOG_ALERT;
+        level = LOG_ALERT;
         break;
     case OT_LOG_LEVEL_CRIT:
-        aLogLevel = LOG_CRIT;
+        level = LOG_CRIT;
         break;
     case OT_LOG_LEVEL_WARN:
-        aLogLevel = LOG_WARNING;
+        level = LOG_WARNING;
         break;
     case OT_LOG_LEVEL_NOTE:
-        aLogLevel = LOG_NOTICE;
+        level = LOG_NOTICE;
         break;
     case OT_LOG_LEVEL_INFO:
-        aLogLevel = LOG_INFO;
+        level = LOG_INFO;
         break;
     case OT_LOG_LEVEL_DEBG:
-        aLogLevel = LOG_DEBUG;
+        level = LOG_DEBUG;
         break;
     default:
         assert(false);
-        aLogLevel = LOG_DEBUG;
         break;
     }
 
+    return level;
+}
+
+#if OPENTHREAD_CONFIG_LOG_INSTANCE_AWARE_API_ENABLE
+OT_TOOL_WEAK void otPlatLogOutput(otInstance *, otLogLevel aLogLevel, const char *aLogLine)
+{
+    syslog(ConvertLogLevelToSyslogLevel(aLogLevel), "%s", aLogLine);
+}
+#else
+OT_TOOL_WEAK void otPlatLog(otLogLevel aLogLevel, otLogRegion, const char *aFormat, ...)
+{
+    va_list args;
+
     va_start(args, aFormat);
-    vsyslog(aLogLevel, aFormat, args);
+    vsyslog(ConvertLogLevelToSyslogLevel(aLogLevel), aFormat, args);
     va_end(args);
 }
+#endif
+
 #endif // OPENTHREAD_CONFIG_LOG_OUTPUT == OPENTHREAD_CONFIG_LOG_OUTPUT_PLATFORM_DEFINED
diff --git a/tests/gtest/fake_platform.cpp b/tests/gtest/fake_platform.cpp
index 29a285e82..fe2b6d932 100644
--- a/tests/gtest/fake_platform.cpp
+++ b/tests/gtest/fake_platform.cpp
@@ -496,6 +496,8 @@ void otPlatDiagRadioReceived(otInstance *, otRadioFrame *, otError) {}
 
 void otPlatDiagAlarmCallback(otInstance *) {}
 
+OT_TOOL_WEAK void otPlatLogOutput(otInstance *, otLogLevel, const char *) {}
+
 OT_TOOL_WEAK void otPlatLog(otLogLevel, otLogRegion, const char *, ...) {}
 
 void *otPlatCAlloc(size_t aNum, size_t aSize) { return calloc(aNum, aSize); }
diff --git a/tests/toranj/openthread-core-toranj-config-simulation.h b/tests/toranj/openthread-core-toranj-config-simulation.h
index b85ab97af..7adc71913 100644
--- a/tests/toranj/openthread-core-toranj-config-simulation.h
+++ b/tests/toranj/openthread-core-toranj-config-simulation.h
@@ -89,6 +89,8 @@
 
 #define OPENTHREAD_CONFIG_LOG_OUTPUT OPENTHREAD_CONFIG_LOG_OUTPUT_PLATFORM_DEFINED
 
+#define OPENTHREAD_CONFIG_LOG_INSTANCE_AWARE_API_ENABLE 1
+
 #define OPENTHREAD_CONFIG_CLI_LOG_INPUT_OUTPUT_ENABLE 1
 
 #define OPENTHREAD_CONFIG_CLI_LOG_INPUT_OUTPUT_LEVEL OT_LOG_LEVEL_INFO
diff --git a/tests/unit/test_dhcp6_pd_client.cpp b/tests/unit/test_dhcp6_pd_client.cpp
index 8cc76444a..0333e2579 100644
--- a/tests/unit/test_dhcp6_pd_client.cpp
+++ b/tests/unit/test_dhcp6_pd_client.cpp
@@ -69,11 +69,11 @@ void AdvanceNowTo(uint32_t aNewNow);
 extern "C" {
 
 #if OPENTHREAD_CONFIG_LOG_OUTPUT == OPENTHREAD_CONFIG_LOG_OUTPUT_PLATFORM_DEFINED
-void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat, ...)
+#if OPENTHREAD_CONFIG_LOG_INSTANCE_AWARE_API_ENABLE
+void otPlatLogOutput(otInstance *, otLogLevel, const char *aLogLine) { printf("   %s\n", aLogLine); }
+#else
+void otPlatLog(otLogLevel, otLogRegion, const char *aFormat, ...)
 {
-    OT_UNUSED_VARIABLE(aLogLevel);
-    OT_UNUSED_VARIABLE(aLogRegion);
-
     va_list args;
 
     printf("   ");
@@ -83,6 +83,7 @@ void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat
     printf("\n");
 }
 #endif
+#endif
 
 //----------------------------------------------------------------------------------------------------------------------
 // otPlatAlarams
diff --git a/tests/unit/test_dns_client.cpp b/tests/unit/test_dns_client.cpp
index 40d211a10..eb5c3e80d 100644
--- a/tests/unit/test_dns_client.cpp
+++ b/tests/unit/test_dns_client.cpp
@@ -138,11 +138,11 @@ void otPlatFree(void *aPtr)
 #endif
 
 #if OPENTHREAD_CONFIG_LOG_OUTPUT == OPENTHREAD_CONFIG_LOG_OUTPUT_PLATFORM_DEFINED
-void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat, ...)
+#if OPENTHREAD_CONFIG_LOG_INSTANCE_AWARE_API_ENABLE
+void otPlatLogOutput(otInstance *, otLogLevel, const char *aLogLine) { printf("   %s\n", aLogLine); }
+#else
+void otPlatLog(otLogLevel, otLogRegion, const char *aFormat, ...)
 {
-    OT_UNUSED_VARIABLE(aLogLevel);
-    OT_UNUSED_VARIABLE(aLogRegion);
-
     va_list args;
 
     printf("   ");
@@ -152,6 +152,7 @@ void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat
     printf("\n");
 }
 #endif
+#endif
 
 } // extern "C"
 
diff --git a/tests/unit/test_dnssd_discovery_proxy.cpp b/tests/unit/test_dnssd_discovery_proxy.cpp
index d242f447d..eeaa7086f 100644
--- a/tests/unit/test_dnssd_discovery_proxy.cpp
+++ b/tests/unit/test_dnssd_discovery_proxy.cpp
@@ -139,11 +139,11 @@ void otPlatFree(void *aPtr)
 #endif
 
 #if OPENTHREAD_CONFIG_LOG_OUTPUT == OPENTHREAD_CONFIG_LOG_OUTPUT_PLATFORM_DEFINED
-void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat, ...)
+#if OPENTHREAD_CONFIG_LOG_INSTANCE_AWARE_API_ENABLE
+void otPlatLogOutput(otInstance *, otLogLevel, const char *aLogLine) { printf("   %s\n", aLogLine); }
+#else
+void otPlatLog(otLogLevel, otLogRegion, const char *aFormat, ...)
 {
-    OT_UNUSED_VARIABLE(aLogLevel);
-    OT_UNUSED_VARIABLE(aLogRegion);
-
     va_list args;
 
     printf("   ");
@@ -153,6 +153,7 @@ void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat
     printf("\n");
 }
 #endif
+#endif
 
 } // extern "C"
 
diff --git a/tests/unit/test_mdns.cpp b/tests/unit/test_mdns.cpp
index 64f86183a..1a6a5f51f 100644
--- a/tests/unit/test_mdns.cpp
+++ b/tests/unit/test_mdns.cpp
@@ -1677,26 +1677,26 @@ static void SendEmtryPtrQueryWithKnownAnswers(const char *aName, const KnownAnsw
 
 extern "C" {
 
-#if OPENTHREAD_CONFIG_LOG_OUTPUT == OPENTHREAD_CONFIG_LOG_OUTPUT_PLATFORM_DEFINED
-void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat, ...)
-{
-    OT_UNUSED_VARIABLE(aLogLevel);
-    OT_UNUSED_VARIABLE(aLogRegion);
-    OT_UNUSED_VARIABLE(aFormat);
-
 #if ENABLE_TEST_LOG
+
+#if OPENTHREAD_CONFIG_LOG_OUTPUT == OPENTHREAD_CONFIG_LOG_OUTPUT_PLATFORM_DEFINED
+#if OPENTHREAD_CONFIG_LOG_INSTANCE_AWARE_API_ENABLE
+void otPlatLogOutput(otInstance *, otLogLevel, const char *aLogLine) { printf("   %s\n", aLogLine); }
+#else
+void otPlatLog(otLogLevel, otLogRegion, const char *aFormat, ...)
+{
     va_list args;
 
     printf("   ");
     va_start(args, aFormat);
     vprintf(aFormat, args);
     va_end(args);
-
     printf("\n");
-#endif
 }
-
 #endif
+#endif
+
+#endif // ENABLE_TEST_LOG
 
 //----------------------------------------------------------------------------------------------------------------------
 // `otPlatAlarm`
diff --git a/tests/unit/test_platform.cpp b/tests/unit/test_platform.cpp
index 728a33319..f74cbaf6c 100644
--- a/tests/unit/test_platform.cpp
+++ b/tests/unit/test_platform.cpp
@@ -280,6 +280,8 @@ OT_TOOL_WEAK otPlatResetReason otPlatGetResetReason(otInstance *) { return OT_PL
 
 OT_TOOL_WEAK void otPlatWakeHost(void) {}
 
+OT_TOOL_WEAK void otPlatLogOutput(otInstance *, otLogLevel, const char *) {}
+
 OT_TOOL_WEAK void otPlatLog(otLogLevel, otLogRegion, const char *, ...) {}
 
 OT_TOOL_WEAK void otPlatSettingsInit(otInstance *, const uint16_t *, uint16_t) {}
diff --git a/tests/unit/test_routing_manager.cpp b/tests/unit/test_routing_manager.cpp
index e97a22f92..fb5c476e8 100644
--- a/tests/unit/test_routing_manager.cpp
+++ b/tests/unit/test_routing_manager.cpp
@@ -242,11 +242,11 @@ void        DiscoverNat64Prefix(const Ip6::Prefix &aPrefix);
 extern "C" {
 
 #if OPENTHREAD_CONFIG_LOG_OUTPUT == OPENTHREAD_CONFIG_LOG_OUTPUT_PLATFORM_DEFINED
-void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat, ...)
+#if OPENTHREAD_CONFIG_LOG_INSTANCE_AWARE_API_ENABLE
+void otPlatLogOutput(otInstance *, otLogLevel, const char *aLogLine) { printf("   %s\n", aLogLine); }
+#else
+void otPlatLog(otLogLevel, otLogRegion, const char *aFormat, ...)
 {
-    OT_UNUSED_VARIABLE(aLogLevel);
-    OT_UNUSED_VARIABLE(aLogRegion);
-
     va_list args;
 
     printf("   ");
@@ -256,6 +256,7 @@ void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat
     printf("\n");
 }
 #endif
+#endif
 
 //----------------------------------------------------------------------------------------------------------------------
 // `otPlatRadio
diff --git a/tests/unit/test_srp_adv_proxy.cpp b/tests/unit/test_srp_adv_proxy.cpp
index 1794a3923..ecb9ce6d3 100644
--- a/tests/unit/test_srp_adv_proxy.cpp
+++ b/tests/unit/test_srp_adv_proxy.cpp
@@ -458,11 +458,11 @@ void otPlatFree(void *aPtr)
 #endif
 
 #if OPENTHREAD_CONFIG_LOG_OUTPUT == OPENTHREAD_CONFIG_LOG_OUTPUT_PLATFORM_DEFINED
-void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat, ...)
+#if OPENTHREAD_CONFIG_LOG_INSTANCE_AWARE_API_ENABLE
+void otPlatLogOutput(otInstance *, otLogLevel, const char *aLogLine) { printf("   %s\n", aLogLine); }
+#else
+void otPlatLog(otLogLevel, otLogRegion, const char *aFormat, ...)
 {
-    OT_UNUSED_VARIABLE(aLogLevel);
-    OT_UNUSED_VARIABLE(aLogRegion);
-
     va_list args;
 
     printf("   ");
@@ -472,6 +472,7 @@ void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat
     printf("\n");
 }
 #endif
+#endif
 
 } // extern "C"
 
diff --git a/tests/unit/test_srp_server.cpp b/tests/unit/test_srp_server.cpp
index a9a2e916c..ae2dde1d4 100644
--- a/tests/unit/test_srp_server.cpp
+++ b/tests/unit/test_srp_server.cpp
@@ -134,11 +134,11 @@ void otPlatFree(void *aPtr)
 #endif
 
 #if OPENTHREAD_CONFIG_LOG_OUTPUT == OPENTHREAD_CONFIG_LOG_OUTPUT_PLATFORM_DEFINED
-void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat, ...)
+#if OPENTHREAD_CONFIG_LOG_INSTANCE_AWARE_API_ENABLE
+void otPlatLogOutput(otInstance *, otLogLevel, const char *aLogLine) { printf("   %s\n", aLogLine); }
+#else
+void otPlatLog(otLogLevel, otLogRegion, const char *aFormat, ...)
 {
-    OT_UNUSED_VARIABLE(aLogLevel);
-    OT_UNUSED_VARIABLE(aLogRegion);
-
     va_list args;
 
     printf("   ");
@@ -148,6 +148,7 @@ void otPlatLog(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat
     printf("\n");
 }
 #endif
+#endif
 
 } // extern "C"