diff --git a/src/core/common/trickle_timer.cpp b/src/core/common/trickle_timer.cpp
index 95bdd09fc..bbd67d48b 100644
--- a/src/core/common/trickle_timer.cpp
+++ b/src/core/common/trickle_timer.cpp
@@ -64,12 +64,10 @@ TrickleTimer::TrickleTimer(Instance &aInstance,
     OT_ASSERT(aTransmitHandler != NULL);
 }
 
-otError TrickleTimer::Start(uint32_t aIntervalMin, uint32_t aIntervalMax, Mode aMode)
+void TrickleTimer::Start(uint32_t aIntervalMin, uint32_t aIntervalMax, Mode aMode)
 {
-    otError error = OT_ERROR_NONE;
-
-    VerifyOrExit(aIntervalMax >= aIntervalMin, error = OT_ERROR_INVALID_ARGS);
-    VerifyOrExit(aIntervalMin != 0 || aIntervalMax != 0, error = OT_ERROR_INVALID_ARGS);
+    OT_ASSERT(aIntervalMax >= aIntervalMin);
+    OT_ASSERT(aIntervalMin != 0 || aIntervalMax != 0);
 
     mIntervalMin = aIntervalMin;
     mIntervalMax = aIntervalMax;
@@ -80,9 +78,6 @@ otError TrickleTimer::Start(uint32_t aIntervalMin, uint32_t aIntervalMax, Mode a
     mInterval = Random::NonCrypto::GetUint32InRange(mIntervalMin, mIntervalMax + 1);
 
     StartNewInterval();
-
-exit:
-    return error;
 }
 
 void TrickleTimer::Stop(void)
diff --git a/src/core/common/trickle_timer.hpp b/src/core/common/trickle_timer.hpp
index 6a13dcfe6..e8ed1d015 100644
--- a/src/core/common/trickle_timer.hpp
+++ b/src/core/common/trickle_timer.hpp
@@ -113,11 +113,8 @@ public:
      * @param[in]  aIntervalMax  The maximum interval for the timer in milliseconds.
      * @param[in]  aMode         The operating mode for the timer.
      *
-     * @retval OT_ERROR_NONE           The timer started successfully.
-     * @retval OT_ERROR_INVALID_ARGS   The given parameters are invalid (i.e., max interval is smaller than min).
-     *
      */
-    otError Start(uint32_t aIntervalMin, uint32_t aIntervalMax, Mode aMode);
+    void Start(uint32_t aIntervalMin, uint32_t aIntervalMax, Mode aMode);
 
     /**
      * This method stops the trickle timer.
diff --git a/src/core/net/dhcp6_client.cpp b/src/core/net/dhcp6_client.cpp
index 36453f67e..8d1666789 100644
--- a/src/core/net/dhcp6_client.cpp
+++ b/src/core/net/dhcp6_client.cpp
@@ -206,8 +206,8 @@ bool Dhcp6Client::ProcessNextIdentityAssociation()
 
         mIdentityAssociationCurrent = &mIdentityAssociations[i];
 
-        IgnoreError(mTrickleTimer.Start(Time::SecToMsec(kTrickleTimerImin), Time::SecToMsec(kTrickleTimerImax),
-                                        TrickleTimer::kModeNormal));
+        mTrickleTimer.Start(Time::SecToMsec(kTrickleTimerImin), Time::SecToMsec(kTrickleTimerImax),
+                            TrickleTimer::kModeNormal);
 
         mTrickleTimer.IndicateInconsistent();
 
diff --git a/src/core/thread/mle_router.cpp b/src/core/thread/mle_router.cpp
index 849d4815b..3380d70af 100644
--- a/src/core/thread/mle_router.cpp
+++ b/src/core/thread/mle_router.cpp
@@ -403,8 +403,8 @@ void MleRouter::ResetAdvertiseInterval(void)
 
     if (!mAdvertiseTimer.IsRunning())
     {
-        IgnoreError(mAdvertiseTimer.Start(Time::SecToMsec(kAdvertiseIntervalMin),
-                                          Time::SecToMsec(kAdvertiseIntervalMax), TrickleTimer::kModeNormal));
+        mAdvertiseTimer.Start(Time::SecToMsec(kAdvertiseIntervalMin), Time::SecToMsec(kAdvertiseIntervalMax),
+                              TrickleTimer::kModeNormal);
     }
 
     mAdvertiseTimer.IndicateInconsistent();
@@ -1783,9 +1783,9 @@ void MleRouter::HandleStateUpdateTimer(void)
             {
                 SendAdvertisement();
 
-                IgnoreError(mAdvertiseTimer.Start(Time::SecToMsec(kReedAdvertiseInterval),
-                                                  Time::SecToMsec(kReedAdvertiseInterval + kReedAdvertiseJitter),
-                                                  TrickleTimer::kModePlainTimer));
+                mAdvertiseTimer.Start(Time::SecToMsec(kReedAdvertiseInterval),
+                                      Time::SecToMsec(kReedAdvertiseInterval + kReedAdvertiseJitter),
+                                      TrickleTimer::kModePlainTimer);
             }
 
             ExitNow();