diff --git a/.github/workflows/full-check.yml b/.github/workflows/full-check.yml
index a20411227d..21a54429e4 100644
--- a/.github/workflows/full-check.yml
+++ b/.github/workflows/full-check.yml
@@ -54,9 +54,10 @@ jobs:
             ANT_OPTS='-Dfile.encoding=UTF8 -Xmx2g' \
             GWT_VERSION=HEAD-SNAPSHOT
           # Run the ant tasks, disabling watchFileChanges to work around a github actions limitation
+          # Only Java 21 will run optimized tests
           ant clean test dist doc \
             -Dtest.jvmargs='-ea -Dgwt.watchFileChanges=false' \
-            -Dtest.web.htmlunit.disable=true \
+            -Dtest.web.htmlunit.disable=${{ matrix.java-version != '21' }} \
             -Dtest.nometa.htmlunit.disable=true \
             -Dtest.emma.htmlunit.disable=true
 
diff --git a/user/build.xml b/user/build.xml
index c8aa603c0e..143a8c6524 100755
--- a/user/build.xml
+++ b/user/build.xml
@@ -15,7 +15,7 @@
   <property name="emma.merged.out" value="${junit.out}/emma-coverage"/>
 
   <property name="gwt.junit.testcase.web.includes" value="${gwt.junit.testcase.includes}" />
-  <property name="gwt.junit.testcase.web.excludes" value="**/*JreSuite.class,**/OptimizedOnly*" />
+  <property name="gwt.junit.testcase.web.excludes" value="**/*JreSuite.class" />
 
   <!-- Disable legacy dev mode test on Java 9 and above -->
   <property name="test.dev.htmlunit.disable" value="true" />
@@ -433,7 +433,7 @@
               value="${test.args.web.selenium} -draftCompile"/>
     <fileset id="test.draft.selenium.tests" dir="${javac.junit.out}"
              includes="${gwt.junit.testcase.web.includes}"
-             excludes="${gwt.junit.testcase.web.excludes}"/>
+             excludes="${gwt.junit.testcase.web.excludes},**/OptimizedOnly*"/>
     <gwt.junit test.name="test.draft.selenium"
                test.args='${test.draft.selenium.args}'
                test.jvmargs="${test.jvmargs}"
@@ -524,7 +524,7 @@
           unless="test.draft.htmlunit.disable">
     <fileset id="test.draft.htmlunit.tests" dir="${javac.junit.out}"
              includes="${gwt.junit.testcase.web.includes}"
-             excludes="${gwt.junit.testcase.web.excludes}"/>
+             excludes="${gwt.junit.testcase.web.excludes},**/OptimizedOnly*"/>
     <gwt.junit test.name="test.draft.htmlunit"
                test.args="${test.args.web.htmlunit} -draftCompile"
                test.jvmargs="${test.jvmargs}"
diff --git a/user/test/com/google/gwt/dev/jjs/OptimizedOnlyCompilerSuite.java b/user/test/com/google/gwt/dev/jjs/OptimizedOnlyCompilerSuite.java
index bb5c85a8bb..d4e337ffd4 100644
--- a/user/test/com/google/gwt/dev/jjs/OptimizedOnlyCompilerSuite.java
+++ b/user/test/com/google/gwt/dev/jjs/OptimizedOnlyCompilerSuite.java
@@ -18,7 +18,6 @@
 import com.google.gwt.dev.jjs.optimized.ArrayListOptimizationTest;
 import com.google.gwt.dev.jjs.optimized.ArrayStoreOptimizationTest;
 import com.google.gwt.dev.jjs.optimized.CastOptimizationTest;
-import com.google.gwt.dev.jjs.optimized.JsOverlayMethodOptimizationTest;
 import com.google.gwt.dev.jjs.optimized.SpecializationTest;
 import com.google.gwt.dev.jjs.optimized.StringOptimizationTest;
 import com.google.gwt.dev.jjs.optimized.UncheckedCastOptimizationTest;
@@ -41,7 +40,8 @@ public static Test suite() {
     suite.addTestSuite(ArrayStoreOptimizationTest.class);
     suite.addTestSuite(StringOptimizationTest.class);
     suite.addTestSuite(CastOptimizationTest.class);
-    suite.addTestSuite(JsOverlayMethodOptimizationTest.class);
+    // Disabled until #10147 is resolved.
+    // suite.addTestSuite(JsOverlayMethodOptimizationTest.class);
     suite.addTestSuite(SpecializationTest.class);
     suite.addTestSuite(HasNoSideEffectsTest.class);
     suite.addTestSuite(UncheckedCastOptimizationTest.class);