diff --git a/jck/jtrunner/JavaTestRunner.java b/jck/jtrunner/JavaTestRunner.java
index 4f1b9a923e..44e59a2926 100644
--- a/jck/jtrunner/JavaTestRunner.java
+++ b/jck/jtrunner/JavaTestRunner.java
@@ -466,6 +466,10 @@ public static boolean jckConfigurationForMultijvmWithNoAgent() throws Exception
 			concurrency = Runtime.getRuntime().availableProcessors() + 1;
 			concurrencyString = String.valueOf(concurrency);
 		}
+		
+		if (platform.contains("zos")) {
+			extraJvmOptions += " -Dfile.encoding=UTF-8";
+		}
 
 		// Set the operating system as 'Windows' for Windows and 'other' for all other operating systems.
 		// If 'other' is specified when executing on Windows, then Windows specific settings such
diff --git a/jck/runtime.api/playlist.xml b/jck/runtime.api/playlist.xml
index 64ff62f647..0ec6c67602 100644
--- a/jck/runtime.api/playlist.xml
+++ b/jck/runtime.api/playlist.xml
@@ -275,14 +275,6 @@
 	</test>
 	<test>
 		<testCaseName>jck-runtime-api-java_lang-Class</testCaseName>
-		<disables>
-			<disable>
-				<comment>Temporarily disabled on z/OS for backlog/issues/666</comment>
-				<platform>.*zos.*</platform>
-				<impl>ibm</impl>
-				<version>11</version>
-			</disable>
-		</disables>
 		<variations>
 			<variation>NoOptions</variation>
 		</variations>
@@ -536,14 +528,6 @@
 	</test>
 	<test>
 		<testCaseName>jck-runtime-api-java_lang</testCaseName>
-		<disables>
-			<disable>
-				<comment>Temporarily disabled on z/OS for backlog/issues/669</comment>
-				<platform>.*zos.*</platform>
-				<impl>ibm</impl>
-				<version>11</version>
-			</disable>
-		</disables>
 		<variations>
 			<variation>NoOptions</variation>
 		</variations>
@@ -683,12 +667,6 @@
 				<version>17</version>
 				<impl>openj9</impl>
 			</disable>
-			<disable>
-				<comment>Temporarily disabled on z/OS for backlog/issues/680</comment>
-				<platform>.*zos.*</platform>
-				<impl>ibm</impl>
-				<version>11</version>
-			</disable>
 		</disables>
 		<variations>
 			<variation>NoOptions</variation>
diff --git a/jck/runtime.vm/playlist.xml b/jck/runtime.vm/playlist.xml
index bbbdd450f6..40bacaeaee 100644
--- a/jck/runtime.vm/playlist.xml
+++ b/jck/runtime.vm/playlist.xml
@@ -136,14 +136,6 @@
 	</test>
 	<test>
 		<testCaseName>jck-runtime-vm-module</testCaseName>
-		<disables>
-			<disable>
-				<comment>Temporarily disabled on z/OS for backlog/issues/583</comment>
-				<platform>.*zos.*</platform>
-				<impl>ibm</impl>
-				<version>11</version>
-			</disable>
-		</disables>
 		<variations>
 			<variation>NoOptions</variation>
 		</variations>