diff --git a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/util/ArrayListSpanAccumulator.java b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/util/ArrayListSpanAccumulator.java
index 2a412d167..774313124 100644
--- a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/util/ArrayListSpanAccumulator.java
+++ b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/util/ArrayListSpanAccumulator.java
@@ -34,7 +34,7 @@ public class ArrayListSpanAccumulator implements SpanReporter {
 
 	public List<Span> getSpans() {
 		synchronized (this.spans) {
-			return this.spans;
+			return new ArrayList<>(this.spans);
 		}
 	}