diff --git a/include/verilated_cov.cpp b/include/verilated_cov.cpp
index dd559427a..bb1893fd8 100644
--- a/include/verilated_cov.cpp
+++ b/include/verilated_cov.cpp
@@ -103,7 +103,7 @@ private:
     using ItemList = std::deque<VerilatedCovImpItem*>;
 
     // MEMBERS
-    VerilatedMutex m_mutex;  // Protects all members
+    mutable VerilatedMutex m_mutex;  // Protects all members
     ValueIndexMap m_valueIndexes VL_GUARDED_BY(m_mutex);  // Unique arbitrary value for values
     IndexValueMap m_indexValues VL_GUARDED_BY(m_mutex);  // Unique arbitrary value for keys
     ItemList m_items VL_GUARDED_BY(m_mutex);  // List of all items
diff --git a/include/verilated_imp.h b/include/verilated_imp.h
index 24456e646..48bd6c42c 100644
--- a/include/verilated_imp.h
+++ b/include/verilated_imp.h
@@ -91,7 +91,7 @@ class VerilatedEvalMsgQueue final {
 
     std::atomic<uint64_t> m_depth;  // Current depth of queue (see comments below)
 
-    VerilatedMutex m_mutex;  // Mutex protecting queue
+    mutable VerilatedMutex m_mutex;  // Mutex protecting queue
     VerilatedThreadQueue m_queue VL_GUARDED_BY(m_mutex);  // Message queue
 public:
     // CONSTRUCTORS
diff --git a/include/verilated_profiler.h b/include/verilated_profiler.h
index 86bfd3d13..b85bd0eb5 100644
--- a/include/verilated_profiler.h
+++ b/include/verilated_profiler.h
@@ -155,7 +155,7 @@ class VlExecutionProfiler final {
 
     // STATE
     static VL_THREAD_LOCAL ExecutionTrace t_trace;  // thread-local trace buffers
-    VerilatedMutex m_mutex;
+    mutable VerilatedMutex m_mutex;
     // Map from thread id to &t_trace of given thread
     std::map<uint32_t, ExecutionTrace*> m_traceps VL_GUARDED_BY(m_mutex);
 
diff --git a/include/verilated_threads.h b/include/verilated_threads.h
index e69ac8929..257c87162 100644
--- a/include/verilated_threads.h
+++ b/include/verilated_threads.h
@@ -150,7 +150,7 @@ private:
     };
 
     // MEMBERS
-    VerilatedMutex m_mutex;
+    mutable VerilatedMutex m_mutex;
     std::condition_variable_any m_cv;
     // Only notify the condition_variable if the worker is waiting
     bool m_waiting VL_GUARDED_BY(m_mutex) = false;
diff --git a/include/verilated_trace.h b/include/verilated_trace.h
index 8069174ee..de000e611 100644
--- a/include/verilated_trace.h
+++ b/include/verilated_trace.h
@@ -47,7 +47,7 @@
 // A simple synchronized first in first out queue
 template <class T> class VerilatedThreadQueue final {  // LCOV_EXCL_LINE  // lcov bug
 private:
-    VerilatedMutex m_mutex;  // Protects m_queue
+    mutable VerilatedMutex m_mutex;  // Protects m_queue
     std::condition_variable_any m_cv;
     std::deque<T> m_queue VL_GUARDED_BY(m_mutex);
 
@@ -208,7 +208,7 @@ protected:
     //=========================================================================
     // Internals available to format specific implementations
 
-    VerilatedMutex m_mutex;  // Ensure dump() etc only called from single thread
+    mutable VerilatedMutex m_mutex;  // Ensure dump() etc only called from single thread
 
     uint32_t nextCode() const { return m_nextCode; }
     uint32_t numSignals() const { return m_numSignals; }