diff --git a/conformance-tests/src/main/java/plugin/PluginWaitReplayFlag.java b/conformance-tests/src/main/java/plugin/PluginWaitReplayFlag.java
new file mode 100644
index 000000000..18cc01613
--- /dev/null
+++ b/conformance-tests/src/main/java/plugin/PluginWaitReplayFlag.java
@@ -0,0 +1,98 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+package plugin;
+
+import java.time.Duration;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Locale;
+import software.amazon.lambda.durable.DurableConfig;
+import software.amazon.lambda.durable.DurableContext;
+import software.amazon.lambda.durable.DurableFuture;
+import software.amazon.lambda.durable.DurableHandler;
+import software.amazon.lambda.durable.ParallelDurableFuture;
+import software.amazon.lambda.durable.config.ParallelConfig;
+import software.amazon.lambda.durable.plugin.DurableExecutionPlugin;
+import software.amazon.lambda.durable.plugin.InvocationInfo;
+import software.amazon.lambda.durable.plugin.OperationEndInfo;
+import software.amazon.lambda.durable.plugin.OperationInfo;
+
+/**
+ * 10-18: Plugin replay flag for a non-terminal wait.
+ *
+ * <p>A parallel operation named "waits" with two branches running concurrently (max-concurrency 2): branch 0 runs a
+ * wait named "short" of 2 seconds and returns "short-done"; branch 1 runs a wait named "long" of 8 seconds and returns
+ * "long-done" (each wait's stable name is supplied via the SDK's real operation-name parameter). Both waits are pending
+ * simultaneously in the first invocation. Filtering to wait-type operations, the plugin logs operation-start with the
+ * stable wait name and the SDK's is-replayed indicator ({@code OperationInfo#isReplay()}), plus operation-end with the
+ * wait name and terminal status. When the execution replays after the 2-second wait completes, the still-NON-terminal
+ * 8-second wait MUST be re-observed with replay=true. Operation ids are deliberately not logged because branch event
+ * ids are nondeterministic under concurrency; stable wait name + replay flag identify the behavior under test without
+ * depending on warm-container state.
+ */
+@SuppressWarnings("deprecation")
+public class PluginWaitReplayFlag extends DurableHandler<Object, List<String>> {
+
+    @Override
+    protected DurableConfig createConfiguration() {
+        return DurableConfig.builder().withPlugins(new WaitReplayFlagPlugin()).build();
+    }
+
+    @Override
+    public List<String> handleRequest(Object input, DurableContext context) {
+        var config = ParallelConfig.builder().maxConcurrency(2).build();
+        var futures = new ArrayList<DurableFuture<String>>();
+        ParallelDurableFuture parallel = context.parallel("waits", config);
+        try (parallel) {
+            futures.add(parallel.branch("branch-0", String.class, branch -> {
+                branch.wait("short", Duration.ofSeconds(2));
+                return "short-done";
+            }));
+            futures.add(parallel.branch("branch-1", String.class, branch -> {
+                branch.wait("long", Duration.ofSeconds(8));
+                return "long-done";
+            }));
+        }
+        return futures.stream().map(DurableFuture::get).toList();
+    }
+
+    private static final class WaitReplayFlagPlugin implements DurableExecutionPlugin {
+        private volatile String executionArn;
+
+        @Override
+        public void onInvocationStart(InvocationInfo info) {
+            this.executionArn = info.durableExecutionArn();
+        }
+
+        @Override
+        public void onOperationStart(OperationInfo info) {
+            if (!PluginSupport.isWait(info.type())) {
+                return;
+            }
+            // pending := non-terminal at hook time, from the hook info's own operation state (no end timestamp
+            // yet) — no cross-invocation state.
+            System.out.println(String.format(
+                    "{\"plugin\": \"CONFPLUGIN\", \"hook\": \"operation-start\", \"type\": \"%s\", \"name\": \"%s\", "
+                            + "\"replay\": %b, \"pending\": %b%s}",
+                    info.type().toUpperCase(Locale.ROOT),
+                    info.name(),
+                    info.isReplay(),
+                    info.endTimestamp() == null,
+                    PluginSupport.arnField(executionArn)));
+        }
+
+        @Override
+        public void onOperationEnd(OperationEndInfo info) {
+            if (!PluginSupport.isWait(info.type())) {
+                return;
+            }
+            System.out.println(String.format(
+                    "{\"plugin\": \"CONFPLUGIN\", \"hook\": \"operation-end\", \"type\": \"%s\", \"name\": \"%s\", "
+                            + "\"status\": \"%s\"%s}",
+                    info.type().toUpperCase(Locale.ROOT),
+                    info.name(),
+                    info.status(),
+                    PluginSupport.arnField(executionArn)));
+        }
+    }
+}
diff --git a/conformance-tests/template_plugin.yaml b/conformance-tests/template_plugin.yaml
index ecc8cac17..8bc377419 100644
--- a/conformance-tests/template_plugin.yaml
+++ b/conformance-tests/template_plugin.yaml
@@ -304,3 +304,19 @@ Resources:
       DurableConfig:
         RetentionPeriodInDays: 7
         ExecutionTimeout: 300
+
+  PluginWaitReplayFlag:
+    Type: AWS::Serverless::Function
+    TestingMetadata:
+      TestDescription: ["10-18"]
+    Properties:
+      CodeUri: .
+      Handler: plugin.PluginWaitReplayFlag
+      Description: A wait still pending during a replay re-fires operation-start with replay=true
+      Role:
+        Fn::GetAtt:
+        - DurableFunctionRole
+        - Arn
+      DurableConfig:
+        RetentionPeriodInDays: 7
+        ExecutionTimeout: 300