diff --git a/crates/client/src/telemetry.rs b/crates/client/src/telemetry.rs
index 2bee99073c..7d1e248ec2 100644
--- a/crates/client/src/telemetry.rs
+++ b/crates/client/src/telemetry.rs
@@ -96,7 +96,7 @@ impl Telemetry {
             log_file: None,
             is_staff: None,
             first_event_date_time: None,
-            event_coalescer: EventCoalescer::new(),
+            event_coalescer: EventCoalescer::new(clock.clone()),
             max_queue_size: MAX_QUEUE_LEN,
         }));
 
diff --git a/crates/client/src/telemetry/event_coalescer.rs b/crates/client/src/telemetry/event_coalescer.rs
index f0efeb38e6..33bcf492f6 100644
--- a/crates/client/src/telemetry/event_coalescer.rs
+++ b/crates/client/src/telemetry/event_coalescer.rs
@@ -1,6 +1,9 @@
-use chrono::{DateTime, Duration, Utc};
+use std::sync::Arc;
 use std::time;
 
+use chrono::{DateTime, Duration, Utc};
+use clock::SystemClock;
+
 const COALESCE_TIMEOUT: time::Duration = time::Duration::from_secs(20);
 const SIMULATED_DURATION_FOR_SINGLE_EVENT: time::Duration = time::Duration::from_millis(1);
 
@@ -12,30 +15,20 @@ struct PeriodData {
 }
 
 pub struct EventCoalescer {
+    clock: Arc<dyn SystemClock>,
     state: Option<PeriodData>,
 }
 
 impl EventCoalescer {
-    pub fn new() -> Self {
-        Self { state: None }
+    pub fn new(clock: Arc<dyn SystemClock>) -> Self {
+        Self { clock, state: None }
     }
 
     pub fn log_event(
         &mut self,
         environment: &'static str,
     ) -> Option<(DateTime<Utc>, DateTime<Utc>, &'static str)> {
-        self.log_event_with_time(Utc::now(), environment)
-    }
-
-    // pub fn close_current_period(&mut self) -> Option<(DateTime<Utc>, DateTime<Utc>)> {
-    //     self.environment.map(|env| self.log_event(env)).flatten()
-    // }
-
-    fn log_event_with_time(
-        &mut self,
-        log_time: DateTime<Utc>,
-        environment: &'static str,
-    ) -> Option<(DateTime<Utc>, DateTime<Utc>, &'static str)> {
+        let log_time = self.clock.utc_now();
         let coalesce_timeout = Duration::from_std(COALESCE_TIMEOUT).unwrap();
 
         let Some(state) = &mut self.state else {
@@ -78,18 +71,22 @@ impl EventCoalescer {
 #[cfg(test)]
 mod tests {
     use chrono::TimeZone;
+    use clock::FakeSystemClock;
 
     use super::*;
 
     #[test]
     fn test_same_context_exceeding_timeout() {
+        let clock = Arc::new(FakeSystemClock::new(
+            Utc.with_ymd_and_hms(1990, 4, 12, 0, 0, 0).unwrap(),
+        ));
         let environment_1 = "environment_1";
-        let mut event_coalescer = EventCoalescer::new();
+        let mut event_coalescer = EventCoalescer::new(clock.clone());
 
         assert_eq!(event_coalescer.state, None);
 
-        let period_start = Utc.with_ymd_and_hms(1990, 4, 12, 0, 0, 0).unwrap();
-        let period_data = event_coalescer.log_event_with_time(period_start, environment_1);
+        let period_start = clock.utc_now();
+        let period_data = event_coalescer.log_event(environment_1);
 
         assert_eq!(period_data, None);
         assert_eq!(
@@ -102,12 +99,12 @@ mod tests {
         );
 
         let within_timeout_adjustment = Duration::from_std(COALESCE_TIMEOUT / 2).unwrap();
-        let mut period_end = period_start;
 
         // Ensure that many calls within the timeout don't start a new period
         for _ in 0..100 {
-            period_end += within_timeout_adjustment;
-            let period_data = event_coalescer.log_event_with_time(period_end, environment_1);
+            clock.advance(within_timeout_adjustment);
+            let period_data = event_coalescer.log_event(environment_1);
+            let period_end = clock.utc_now();
 
             assert_eq!(period_data, None);
             assert_eq!(
@@ -120,10 +117,12 @@ mod tests {
             );
         }
 
+        let period_end = clock.utc_now();
         let exceed_timeout_adjustment = Duration::from_std(COALESCE_TIMEOUT * 2).unwrap();
         // Logging an event exceeding the timeout should start a new period
-        let new_period_start = period_end + exceed_timeout_adjustment;
-        let period_data = event_coalescer.log_event_with_time(new_period_start, environment_1);
+        clock.advance(exceed_timeout_adjustment);
+        let new_period_start = clock.utc_now();
+        let period_data = event_coalescer.log_event(environment_1);
 
         assert_eq!(period_data, Some((period_start, period_end, environment_1)));
         assert_eq!(
@@ -138,13 +137,16 @@ mod tests {
 
     #[test]
     fn test_different_environment_under_timeout() {
+        let clock = Arc::new(FakeSystemClock::new(
+            Utc.with_ymd_and_hms(1990, 4, 12, 0, 0, 0).unwrap(),
+        ));
         let environment_1 = "environment_1";
-        let mut event_coalescer = EventCoalescer::new();
+        let mut event_coalescer = EventCoalescer::new(clock.clone());
 
         assert_eq!(event_coalescer.state, None);
 
-        let period_start = Utc.with_ymd_and_hms(1990, 4, 12, 0, 0, 0).unwrap();
-        let period_data = event_coalescer.log_event_with_time(period_start, environment_1);
+        let period_start = clock.utc_now();
+        let period_data = event_coalescer.log_event(environment_1);
 
         assert_eq!(period_data, None);
         assert_eq!(
@@ -157,8 +159,9 @@ mod tests {
         );
 
         let within_timeout_adjustment = Duration::from_std(COALESCE_TIMEOUT / 2).unwrap();
-        let period_end = period_start + within_timeout_adjustment;
-        let period_data = event_coalescer.log_event_with_time(period_end, environment_1);
+        clock.advance(within_timeout_adjustment);
+        let period_end = clock.utc_now();
+        let period_data = event_coalescer.log_event(environment_1);
 
         assert_eq!(period_data, None);
         assert_eq!(
@@ -170,10 +173,12 @@ mod tests {
             })
         );
 
+        clock.advance(within_timeout_adjustment);
+
         // Logging an event within the timeout but with a different environment should start a new period
-        let period_end = period_end + within_timeout_adjustment;
+        let period_end = clock.utc_now();
         let environment_2 = "environment_2";
-        let period_data = event_coalescer.log_event_with_time(period_end, environment_2);
+        let period_data = event_coalescer.log_event(environment_2);
 
         assert_eq!(period_data, Some((period_start, period_end, environment_1)));
         assert_eq!(
@@ -188,13 +193,16 @@ mod tests {
 
     #[test]
     fn test_switching_environment_while_within_timeout() {
+        let clock = Arc::new(FakeSystemClock::new(
+            Utc.with_ymd_and_hms(1990, 4, 12, 0, 0, 0).unwrap(),
+        ));
         let environment_1 = "environment_1";
-        let mut event_coalescer = EventCoalescer::new();
+        let mut event_coalescer = EventCoalescer::new(clock.clone());
 
         assert_eq!(event_coalescer.state, None);
 
-        let period_start = Utc.with_ymd_and_hms(1990, 4, 12, 0, 0, 0).unwrap();
-        let period_data = event_coalescer.log_event_with_time(period_start, environment_1);
+        let period_start = clock.utc_now();
+        let period_data = event_coalescer.log_event(environment_1);
 
         assert_eq!(period_data, None);
         assert_eq!(
@@ -207,9 +215,10 @@ mod tests {
         );
 
         let within_timeout_adjustment = Duration::from_std(COALESCE_TIMEOUT / 2).unwrap();
-        let period_end = period_start + within_timeout_adjustment;
+        clock.advance(within_timeout_adjustment);
+        let period_end = clock.utc_now();
         let environment_2 = "environment_2";
-        let period_data = event_coalescer.log_event_with_time(period_end, environment_2);
+        let period_data = event_coalescer.log_event(environment_2);
 
         assert_eq!(period_data, Some((period_start, period_end, environment_1)));
         assert_eq!(
@@ -221,22 +230,26 @@ mod tests {
             })
         );
     }
-    // // 0                   20                  40                  60
-    // // |-------------------|-------------------|-------------------|-------------------
-    // // |--------|----------env change
-    // //          |-------------------
-    // // |period_start       |period_end
-    // //                     |new_period_start
+
+    // 0                   20                  40                  60
+    // |-------------------|-------------------|-------------------|-------------------
+    // |--------|----------env change
+    //          |-------------------
+    // |period_start       |period_end
+    //                     |new_period_start
 
     #[test]
     fn test_switching_environment_while_exceeding_timeout() {
+        let clock = Arc::new(FakeSystemClock::new(
+            Utc.with_ymd_and_hms(1990, 4, 12, 0, 0, 0).unwrap(),
+        ));
         let environment_1 = "environment_1";
-        let mut event_coalescer = EventCoalescer::new();
+        let mut event_coalescer = EventCoalescer::new(clock.clone());
 
         assert_eq!(event_coalescer.state, None);
 
-        let period_start = Utc.with_ymd_and_hms(1990, 4, 12, 0, 0, 0).unwrap();
-        let period_data = event_coalescer.log_event_with_time(period_start, environment_1);
+        let period_start = clock.utc_now();
+        let period_data = event_coalescer.log_event(environment_1);
 
         assert_eq!(period_data, None);
         assert_eq!(
@@ -249,9 +262,10 @@ mod tests {
         );
 
         let exceed_timeout_adjustment = Duration::from_std(COALESCE_TIMEOUT * 2).unwrap();
-        let period_end = period_start + exceed_timeout_adjustment;
+        clock.advance(exceed_timeout_adjustment);
+        let period_end = clock.utc_now();
         let environment_2 = "environment_2";
-        let period_data = event_coalescer.log_event_with_time(period_end, environment_2);
+        let period_data = event_coalescer.log_event(environment_2);
 
         assert_eq!(
             period_data,
@@ -270,6 +284,7 @@ mod tests {
             })
         );
     }
+
     // 0                   20                  40                  60
     // |-------------------|-------------------|-------------------|-------------------
     // |--------|----------------------------------------env change