diff --git a/google-cloud-spanner/pom.xml b/google-cloud-spanner/pom.xml
index 8a79e70362e..7ea8a1cb5ea 100644
--- a/google-cloud-spanner/pom.xml
+++ b/google-cloud-spanner/pom.xml
@@ -107,7 +107,7 @@
             </goals>
             <configuration>
               <groups>com.google.cloud.spanner.ParallelIntegrationTest</groups>
-              <forkCount>8</forkCount>
+              <forkCount>12</forkCount>
               <reuseForks>true</reuseForks>
               <groups>com.google.cloud.spanner.ParallelIntegrationTest</groups>
             </configuration>
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/it/ITBulkConnectionTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/it/ITBulkConnectionTest.java
index 9cc46e6ee13..42358a647a1 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/it/ITBulkConnectionTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/it/ITBulkConnectionTest.java
@@ -36,8 +36,8 @@
 
 /**
  * Test opening multiple generic (not JDBC) Spanner connections. This test should not be run in
- * parallel with other tests, as it tries to close all active connections, and should not try to
- * close connections of other integration tests.
+ * parallel with other tests in the same JVM, as it tries to close all active connections, and
+ * should not try to close connections of other integration tests.
  */
 @Category(SerialIntegrationTest.class)
 @RunWith(JUnit4.class)
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/it/ITQueryOptionsTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/it/ITQueryOptionsTest.java
index 09f4ada43a8..62eba4f4315 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/it/ITQueryOptionsTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/it/ITQueryOptionsTest.java
@@ -16,12 +16,18 @@
 
 package com.google.cloud.spanner.connection.it;
 
+import com.google.cloud.spanner.ParallelIntegrationTest;
 import com.google.cloud.spanner.connection.ITAbstractSpannerTest;
 import com.google.cloud.spanner.connection.SqlScriptVerifier;
 import com.google.cloud.spanner.connection.SqlScriptVerifier.SpannerGenericConnection;
 import org.junit.Before;
 import org.junit.Test;
+import org.junit.experimental.categories.Category;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
 
+@Category(ParallelIntegrationTest.class)
+@RunWith(JUnit4.class)
 public class ITQueryOptionsTest extends ITAbstractSpannerTest {
 
   private static final String TEST_QUERY_OPTIONS = "ITSqlScriptTest_TestQueryOptions.sql";
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITAsyncAPITest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITAsyncAPITest.java
index ebd3ab4883f..1e408fadf33 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITAsyncAPITest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITAsyncAPITest.java
@@ -42,7 +42,7 @@
 import com.google.cloud.spanner.KeySet;
 import com.google.cloud.spanner.Mutation;
 import com.google.cloud.spanner.Options;
-import com.google.cloud.spanner.SerialIntegrationTest;
+import com.google.cloud.spanner.ParallelIntegrationTest;
 import com.google.cloud.spanner.SpannerException;
 import com.google.cloud.spanner.Statement;
 import com.google.cloud.spanner.Struct;
@@ -68,7 +68,7 @@
 import org.junit.runners.JUnit4;
 
 /** Integration tests for asynchronous APIs. */
-@Category(SerialIntegrationTest.class)
+@Category(ParallelIntegrationTest.class)
 @RunWith(JUnit4.class)
 public class ITAsyncAPITest {
   @ClassRule public static IntegrationTestEnv env = new IntegrationTestEnv();
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITAsyncExamplesTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITAsyncExamplesTest.java
index 87f26da9049..dc5abd77afd 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITAsyncExamplesTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITAsyncExamplesTest.java
@@ -33,8 +33,8 @@
 import com.google.cloud.spanner.Key;
 import com.google.cloud.spanner.KeySet;
 import com.google.cloud.spanner.Mutation;
+import com.google.cloud.spanner.ParallelIntegrationTest;
 import com.google.cloud.spanner.ReadOnlyTransaction;
-import com.google.cloud.spanner.SerialIntegrationTest;
 import com.google.cloud.spanner.SpannerException;
 import com.google.cloud.spanner.Statement;
 import com.google.cloud.spanner.Struct;
@@ -59,7 +59,7 @@
 import org.junit.runners.JUnit4;
 
 /** Integration tests for asynchronous APIs. */
-@Category(SerialIntegrationTest.class)
+@Category(ParallelIntegrationTest.class)
 @RunWith(JUnit4.class)
 public class ITAsyncExamplesTest {
   @ClassRule public static IntegrationTestEnv env = new IntegrationTestEnv();