diff --git a/iceoryx2-cal/src/monitoring/file_lock.rs b/iceoryx2-cal/src/monitoring/file_lock.rs
index 42d57cb8b..4dfa7fb6c 100644
--- a/iceoryx2-cal/src/monitoring/file_lock.rs
+++ b/iceoryx2-cal/src/monitoring/file_lock.rs
@@ -150,7 +150,7 @@ impl NamedConcept for Monitor {
 }
 
 impl MonitoringMonitor for Monitor {
-    fn state(&mut self) -> Result<super::State, MonitoringStateError> {
+    fn state(&self) -> Result<super::State, MonitoringStateError> {
         let msg = "Unable to acquire monitor state";
 
         match self.monitor.state() {
diff --git a/iceoryx2-cal/src/monitoring/mod.rs b/iceoryx2-cal/src/monitoring/mod.rs
index 4270d2e8a..ca87d4eaf 100644
--- a/iceoryx2-cal/src/monitoring/mod.rs
+++ b/iceoryx2-cal/src/monitoring/mod.rs
@@ -50,7 +50,7 @@ pub enum MonitoringStateError {
 pub trait MonitoringToken: NamedConcept {}
 
 pub trait MonitoringMonitor: NamedConcept {
-    fn state(&mut self) -> Result<State, MonitoringStateError>;
+    fn state(&self) -> Result<State, MonitoringStateError>;
 }
 
 pub trait MonitoringBuilder<T: Monitoring>: NamedConceptBuilder<T> {