diff --git a/include/openthread/link.h b/include/openthread/link.h
index 446e42700..ef099a278 100644
--- a/include/openthread/link.h
+++ b/include/openthread/link.h
@@ -801,26 +801,6 @@ otError otLinkSetEnabled(otInstance *aInstance, bool aEnable);
  */
 bool otLinkIsEnabled(otInstance *aInstance);
 
-/**
- * This function gets the minimum channel number of IEEE 802.15.4 physical layer.
- *
- * @param[in]  aInstance  A pointer to an OpenThread instance.
- *
- * @returns The minimum channel number.
- *
- */
-OTAPI uint8_t OTCALL otLinkGetPhyChannelMin(otInstance *aInstance);
-
-/**
- * This function gets the maximum channel number of IEEE 802.15.4 physical layer.
- *
- * @param[in]  aInstance  A pointer to an OpenThread instance.
- *
- * @returns The maximum channel number.
- *
- */
-OTAPI uint8_t OTCALL otLinkGetPhyChannelMax(otInstance *aInstance);
-
 /**
  * @}
  *
diff --git a/src/cli/cli.cpp b/src/cli/cli.cpp
index 561dd1321..4eebdce42 100644
--- a/src/cli/cli.cpp
+++ b/src/cli/cli.cpp
@@ -554,16 +554,25 @@ void Interpreter::ProcessChannel(int argc, char *argv[])
             mServer->OutputFormat("enabled: %d\r\n", otChannelMonitorIsEnabled(mInstance));
             if (otChannelMonitorIsEnabled(mInstance))
             {
+                uint32_t channelMask = otLinkGetSupportedChannelMask(mInstance);
+                uint8_t  channelNum  = sizeof(channelMask) * CHAR_BIT;
+
                 mServer->OutputFormat("interval: %lu\r\n", otChannelMonitorGetSampleInterval(mInstance));
                 mServer->OutputFormat("threshold: %d\r\n", otChannelMonitorGetRssiThreshold(mInstance));
                 mServer->OutputFormat("window: %lu\r\n", otChannelMonitorGetSampleWindow(mInstance));
                 mServer->OutputFormat("count: %lu\r\n", otChannelMonitorGetSampleCount(mInstance));
 
                 mServer->OutputFormat("occupancies:\r\n");
-                for (uint8_t channel = otLinkGetPhyChannelMin(mInstance); channel <= otLinkGetPhyChannelMax(mInstance);
-                     channel++)
+                for (uint8_t channel = 0; channel < channelNum; channel++)
                 {
-                    uint32_t occupancy = otChannelMonitorGetChannelOccupancy(mInstance, channel);
+                    uint32_t occupancy = 0;
+
+                    if (!((1UL << channel) & channelMask))
+                    {
+                        continue;
+                    }
+
+                    occupancy = otChannelMonitorGetChannelOccupancy(mInstance, channel);
 
                     mServer->OutputFormat("ch %d (0x%04x) ", channel, occupancy);
                     occupancy = (occupancy * 10000) / 0xffff;
diff --git a/src/core/api/link_api.cpp b/src/core/api/link_api.cpp
index 27203d8c5..cf13e750c 100644
--- a/src/core/api/link_api.cpp
+++ b/src/core/api/link_api.cpp
@@ -431,15 +431,3 @@ uint16_t otLinkGetCcaFailureRate(otInstance *aInstance)
 
     return instance.Get<Mac::Mac>().GetCcaFailureRate();
 }
-
-uint8_t otLinkGetPhyChannelMin(otInstance *aInstance)
-{
-    OT_UNUSED_VARIABLE(aInstance);
-    return Phy::kChannelMin;
-}
-
-uint8_t otLinkGetPhyChannelMax(otInstance *aInstance)
-{
-    OT_UNUSED_VARIABLE(aInstance);
-    return Phy::kChannelMax;
-}
diff --git a/src/diag/diag_process.cpp b/src/diag/diag_process.cpp
index 16cf2396b..c34a9aa13 100644
--- a/src/diag/diag_process.cpp
+++ b/src/diag/diag_process.cpp
@@ -40,6 +40,7 @@
 #include <openthread/link.h>
 
 #include "common/code_utils.hpp"
+#include "phy/phy.hpp"
 #include "utils/wrap_string.h"
 
 namespace ot {
@@ -191,8 +192,7 @@ void Diag::ProcessChannel(int aArgCount, char *aArgVector[], char *aOutput, size
         long value;
 
         SuccessOrExit(error = ParseLong(aArgVector[0], value));
-        VerifyOrExit(value >= otLinkGetPhyChannelMin(sInstance) && value <= otLinkGetPhyChannelMax(sInstance),
-                     error = OT_ERROR_INVALID_ARGS);
+        VerifyOrExit(value >= Phy::kChannelMin && value <= Phy::kChannelMax, error = OT_ERROR_INVALID_ARGS);
 
         sChannel = static_cast<uint8_t>(value);
         otPlatRadioReceive(sInstance, sChannel);
diff --git a/src/ncp/ncp_base_mtd.cpp b/src/ncp/ncp_base_mtd.cpp
index 649443882..83294edb7 100644
--- a/src/ncp/ncp_base_mtd.cpp
+++ b/src/ncp/ncp_base_mtd.cpp
@@ -2060,10 +2060,17 @@ template <> otError NcpBase::HandlePropertyGet<SPINEL_PROP_CHANNEL_MONITOR_SAMPL
 
 template <> otError NcpBase::HandlePropertyGet<SPINEL_PROP_CHANNEL_MONITOR_CHANNEL_OCCUPANCY>(void)
 {
-    otError error = OT_ERROR_NONE;
+    otError  error       = OT_ERROR_NONE;
+    uint32_t channelMask = otLinkGetSupportedChannelMask(mInstance);
+    uint8_t  channelNum  = sizeof(channelMask) * CHAR_BIT;
 
-    for (uint8_t channel = otLinkGetPhyChannelMin(mInstance); channel <= otLinkGetPhyChannelMax(mInstance); channel++)
+    for (uint8_t channel = 0; channel < channelNum; channel++)
     {
+        if (!((1UL << channel) & channelMask))
+        {
+            continue;
+        }
+
         SuccessOrExit(error = mEncoder.OpenStruct());
 
         SuccessOrExit(error = mEncoder.WriteUint8(channel));