diff --git a/httpclient5-testing/src/test/java/org/apache/hc/client5/testing/external/HttpAsyncClientCompatibilityTest.java b/httpclient5-testing/src/test/java/org/apache/hc/client5/testing/external/HttpAsyncClientCompatibilityTest.java
index 763d9c3a1..c5903c5a4 100644
--- a/httpclient5-testing/src/test/java/org/apache/hc/client5/testing/external/HttpAsyncClientCompatibilityTest.java
+++ b/httpclient5-testing/src/test/java/org/apache/hc/client5/testing/external/HttpAsyncClientCompatibilityTest.java
@@ -95,6 +95,13 @@ public class HttpAsyncClientCompatibilityTest {
                 new HttpAsyncClientCompatibilityTest(
                         HttpVersionPolicy.NEGOTIATE,
                         new HttpHost("https", "test-httpd", 8443), new HttpHost("localhost", 8889),
+                        new UsernamePasswordCredentials("squid", "nopassword".toCharArray())),
+                new HttpAsyncClientCompatibilityTest(
+                        HttpVersionPolicy.FORCE_HTTP_2,
+                        new HttpHost("https", "test-httpd", 8443), new HttpHost("localhost", 8888), null),
+                new HttpAsyncClientCompatibilityTest(
+                        HttpVersionPolicy.FORCE_HTTP_2,
+                        new HttpHost("https", "test-httpd", 8443), new HttpHost("localhost", 8889),
                         new UsernamePasswordCredentials("squid", "nopassword".toCharArray()))
         };
         for (final HttpAsyncClientCompatibilityTest test: tests) {
diff --git a/httpclient5/src/main/java/org/apache/hc/client5/http/impl/async/InternalHttpAsyncClient.java b/httpclient5/src/main/java/org/apache/hc/client5/http/impl/async/InternalHttpAsyncClient.java
index c2b7c5c69..2dc8a4218 100644
--- a/httpclient5/src/main/java/org/apache/hc/client5/http/impl/async/InternalHttpAsyncClient.java
+++ b/httpclient5/src/main/java/org/apache/hc/client5/http/impl/async/InternalHttpAsyncClient.java
@@ -101,11 +101,7 @@ public final class InternalHttpAsyncClient extends InternalAbstractHttpAsyncClie
 
     @Override
     HttpRoute determineRoute(final HttpHost httpHost, final HttpClientContext clientContext) throws HttpException {
-        final HttpRoute route = routePlanner.determineRoute(httpHost, clientContext);
-        if (route.isTunnelled() && versionPolicy == HttpVersionPolicy.FORCE_HTTP_2) {
-            throw new HttpException("HTTP/2 tunneling not supported");
-        }
-        return route;
+        return routePlanner.determineRoute(httpHost, clientContext);
     }
 
 }
diff --git a/httpclient5/src/main/java/org/apache/hc/client5/http/impl/nio/PoolingAsyncClientConnectionManager.java b/httpclient5/src/main/java/org/apache/hc/client5/http/impl/nio/PoolingAsyncClientConnectionManager.java
index 3bc64abff..3617b592e 100644
--- a/httpclient5/src/main/java/org/apache/hc/client5/http/impl/nio/PoolingAsyncClientConnectionManager.java
+++ b/httpclient5/src/main/java/org/apache/hc/client5/http/impl/nio/PoolingAsyncClientConnectionManager.java
@@ -67,6 +67,7 @@ import org.apache.hc.core5.http.nio.HandlerFactory;
 import org.apache.hc.core5.http.nio.command.RequestExecutionCommand;
 import org.apache.hc.core5.http.nio.ssl.TlsStrategy;
 import org.apache.hc.core5.http.protocol.HttpContext;
+import org.apache.hc.core5.http2.HttpVersionPolicy;
 import org.apache.hc.core5.http2.nio.command.PingCommand;
 import org.apache.hc.core5.http2.nio.support.BasicPingHandler;
 import org.apache.hc.core5.http2.ssl.ApplicationProtocol;
@@ -405,7 +406,12 @@ public class PoolingAsyncClientConnectionManager implements AsyncClientConnectio
             LOG.debug("{} connecting endpoint to {} ({})", ConnPoolSupport.getId(endpoint), host, connectTimeout);
         }
         final Future<ManagedAsyncClientConnection> connectFuture = connectionOperator.connect(
-                connectionInitiator, host, localAddress, connectTimeout, attachment, new FutureCallback<ManagedAsyncClientConnection>() {
+                connectionInitiator,
+                host,
+                localAddress,
+                connectTimeout,
+                route.isTunnelled() ? HttpVersionPolicy.FORCE_HTTP_1 : attachment,
+                new FutureCallback<ManagedAsyncClientConnection>() {
 
                     @Override
                     public void completed(final ManagedAsyncClientConnection connection) {