diff --git a/sdks/java/io/cassandra/src/main/java/org/apache/beam/sdk/io/cassandra/ConnectionManager.java b/sdks/java/io/cassandra/src/main/java/org/apache/beam/sdk/io/cassandra/ConnectionManager.java
index 8a60275c707a..c2fb2f56d4eb 100644
--- a/sdks/java/io/cassandra/src/main/java/org/apache/beam/sdk/io/cassandra/ConnectionManager.java
+++ b/sdks/java/io/cassandra/src/main/java/org/apache/beam/sdk/io/cassandra/ConnectionManager.java
@@ -58,7 +58,7 @@ private static String readToSessionHash(Read<?> read) {
     return readToClusterHash(read) + read.keyspace().get();
   }
 
-  static Session getSession(Read<?> read) {
+  static synchronized Session getSession(Read<?> read) {
     String clusterHash = readToClusterHash(read);
     String sessionHash = readToSessionHash(read);