diff --git a/src/ncp/ncp_base_radio.cpp b/src/ncp/ncp_base_radio.cpp
index e58f1d5f9..3e38620e1 100644
--- a/src/ncp/ncp_base_radio.cpp
+++ b/src/ncp/ncp_base_radio.cpp
@@ -90,10 +90,7 @@ void NcpBase::LinkRawReceiveDone(otRadioFrame *aFrame, otError aError)
     SuccessOrExit(mEncoder.WriteUint8(aFrame->mChannel));           // 802.15.4 channel (Receive channel)
     SuccessOrExit(mEncoder.WriteUint8(aFrame->mInfo.mRxInfo.mLqi)); // 802.15.4 LQI
 
-    SuccessOrExit(mEncoder.WriteUint32(
-        static_cast<uint32_t>(aFrame->mInfo.mRxInfo.mTimestamp / 1000))); // The timestamp milliseconds
-    SuccessOrExit(
-        mEncoder.WriteUint16(aFrame->mInfo.mRxInfo.mTimestamp % 1000)); // The timestamp microseconds, offset to mMsec
+    SuccessOrExit(mEncoder.WriteUint64(aFrame->mInfo.mRxInfo.mTimestamp)); // The timestamp in microseconds
 
     SuccessOrExit(mEncoder.CloseStruct());
 
@@ -137,13 +134,10 @@ void NcpBase::LinkRawTransmitDone(otRadioFrame *aFrame, otRadioFrame *aAckFrame,
             SuccessOrExit(mEncoder.WriteInt8(-128));                           // Noise Floor (Currently unused)
             SuccessOrExit(mEncoder.WriteUint16(0));                            // Flags
 
-            SuccessOrExit(mEncoder.OpenStruct());                              // PHY-data
-            SuccessOrExit(mEncoder.WriteUint8(aAckFrame->mChannel));           // Receive channel
-            SuccessOrExit(mEncoder.WriteUint8(aAckFrame->mInfo.mRxInfo.mLqi)); // Link Quality Indicator
-            SuccessOrExit(mEncoder.WriteUint32(
-                static_cast<uint32_t>(aAckFrame->mInfo.mRxInfo.mTimestamp / 1000))); // The timestamp milliseconds
-            SuccessOrExit(mEncoder.WriteUint16(aAckFrame->mInfo.mRxInfo.mTimestamp %
-                                               1000)); // The timestamp microseconds, offset to mMsec
+            SuccessOrExit(mEncoder.OpenStruct());                                     // PHY-data
+            SuccessOrExit(mEncoder.WriteUint8(aAckFrame->mChannel));                  // Receive channel
+            SuccessOrExit(mEncoder.WriteUint8(aAckFrame->mInfo.mRxInfo.mLqi));        // Link Quality Indicator
+            SuccessOrExit(mEncoder.WriteUint64(aAckFrame->mInfo.mRxInfo.mTimestamp)); // The timestamp in microseconds
 
             SuccessOrExit(mEncoder.CloseStruct());
 
diff --git a/src/posix/platform/radio_spinel.cpp b/src/posix/platform/radio_spinel.cpp
index b69b30f69..b11fe2460 100644
--- a/src/posix/platform/radio_spinel.cpp
+++ b/src/posix/platform/radio_spinel.cpp
@@ -612,29 +612,25 @@ otError RadioSpinel::ParseRadioFrame(otRadioFrame &aFrame, const uint8_t *aBuffe
     otError        error        = OT_ERROR_NONE;
     uint16_t       flags        = 0;
     int8_t         noiseFloor   = -128;
-    uint32_t       msec         = 0;
-    uint16_t       usec         = 0;
     spinel_size_t  size         = OT_RADIO_FRAME_MAX_SIZE;
     unsigned int   receiveError = 0;
     spinel_ssize_t unpacked;
 
-    // Timestamp is ms + us.
-    unpacked =
-        spinel_datatype_unpack_in_place(aBuffer, aLength,
-                                        SPINEL_DATATYPE_DATA_WLEN_S                              // Frame
-                                                        SPINEL_DATATYPE_INT8_S                   // RSSI
-                                                        SPINEL_DATATYPE_INT8_S                   // Noise Floor
-                                                        SPINEL_DATATYPE_UINT16_S                 // Flags
-                                                        SPINEL_DATATYPE_STRUCT_S(                // PHY-data
-                                                            SPINEL_DATATYPE_UINT8_S              // 802.15.4 channel
-                                                                        SPINEL_DATATYPE_UINT8_S  // 802.15.4 LQI
-                                                                        SPINEL_DATATYPE_UINT32_S // Timestamp (ms).
-                                                                        SPINEL_DATATYPE_UINT16_S // Timestamp (us).
-                                                            ) SPINEL_DATATYPE_STRUCT_S(          // Vendor-data
-                                                            SPINEL_DATATYPE_UINT_PACKED_S        // Receive error
-                                                            ),
-                                        aFrame.mPsdu, &size, &aFrame.mInfo.mRxInfo.mRssi, &noiseFloor, &flags,
-                                        &aFrame.mChannel, &aFrame.mInfo.mRxInfo.mLqi, &msec, &usec, &receiveError);
+    unpacked = spinel_datatype_unpack_in_place(aBuffer, aLength,
+                                               SPINEL_DATATYPE_DATA_WLEN_S                          // Frame
+                                                               SPINEL_DATATYPE_INT8_S               // RSSI
+                                                               SPINEL_DATATYPE_INT8_S               // Noise Floor
+                                                               SPINEL_DATATYPE_UINT16_S             // Flags
+                                                               SPINEL_DATATYPE_STRUCT_S(            // PHY-data
+                                                                   SPINEL_DATATYPE_UINT8_S          // 802.15.4 channel
+                                                                           SPINEL_DATATYPE_UINT8_S  // 802.15.4 LQI
+                                                                           SPINEL_DATATYPE_UINT64_S // Timestamp (us).
+                                                                   ) SPINEL_DATATYPE_STRUCT_S(      // Vendor-data
+                                                                   SPINEL_DATATYPE_UINT_PACKED_S    // Receive error
+                                                                   ),
+                                               aFrame.mPsdu, &size, &aFrame.mInfo.mRxInfo.mRssi, &noiseFloor, &flags,
+                                               &aFrame.mChannel, &aFrame.mInfo.mRxInfo.mLqi,
+                                               &aFrame.mInfo.mRxInfo.mTimestamp, &receiveError);
 
     VerifyOrExit(unpacked > 0, error = OT_ERROR_PARSE);
 
@@ -642,7 +638,6 @@ otError RadioSpinel::ParseRadioFrame(otRadioFrame &aFrame, const uint8_t *aBuffe
     {
         aFrame.mLength = static_cast<uint8_t>(size);
 
-        aFrame.mInfo.mRxInfo.mTimestamp             = msec * 1000 + usec;
         aFrame.mInfo.mRxInfo.mAckedWithFramePending = ((flags & SPINEL_MD_FLAG_ACKED_FP) != 0);
     }
     else if (receiveError < OT_NUM_ERRORS)