diff --git a/Sources/OpenTelemetrySdk/Trace/RecordEventsReadableSpan.swift b/Sources/OpenTelemetrySdk/Trace/RecordEventsReadableSpan.swift
index 705ff41d..0460d637 100644
--- a/Sources/OpenTelemetrySdk/Trace/RecordEventsReadableSpan.swift
+++ b/Sources/OpenTelemetrySdk/Trace/RecordEventsReadableSpan.swift
@@ -195,26 +195,28 @@ public class RecordEventsReadableSpan: ReadableSpan {
     }
 
     public func toSpanData() -> SpanData {
-        return SpanData(traceId: context.traceId,
-                        spanId: context.spanId,
-                        traceFlags: context.traceFlags,
-                        traceState: context.traceState,
-                        parentSpanId: parentContext?.spanId,
-                        resource: resource,
-                        instrumentationScope: instrumentationScopeInfo,
-                        name: name,
-                        kind: kind,
-                        startTime: startTime,
-                        attributes: attributes.attributes,
-                        events: adaptEvents(),
-                        links: adaptLinks(),
-                        status: status,
-                        endTime: endTime ?? clock.now,
-                        hasRemoteParent: hasRemoteParent,
-                        hasEnded: hasEnded,
-                        totalRecordedEvents: getTotalRecordedEvents(),
-                        totalRecordedLinks: totalRecordedLinks,
-                        totalAttributeCount: totalAttributeCount)
+        attributesSyncLock.withLock {
+            return SpanData(traceId: context.traceId,
+                            spanId: context.spanId,
+                            traceFlags: context.traceFlags,
+                            traceState: context.traceState,
+                            parentSpanId: parentContext?.spanId,
+                            resource: resource,
+                            instrumentationScope: instrumentationScopeInfo,
+                            name: name,
+                            kind: kind,
+                            startTime: startTime,
+                            attributes: attributes.attributes,
+                            events: adaptEvents(),
+                            links: adaptLinks(),
+                            status: status,
+                            endTime: endTime ?? clock.now,
+                            hasRemoteParent: hasRemoteParent,
+                            hasEnded: hasEnded,
+                            totalRecordedEvents: getTotalRecordedEvents(),
+                            totalRecordedLinks: totalRecordedLinks,
+                            totalAttributeCount: totalAttributeCount)
+        }
     }
 
     private func adaptEvents() -> [SpanData.Event] {