diff --git a/java/src/org/openqa/selenium/remote/HttpCommandExecutor.java b/java/src/org/openqa/selenium/remote/HttpCommandExecutor.java
index 03fc84bc45b19..1eb3283eae014 100644
--- a/java/src/org/openqa/selenium/remote/HttpCommandExecutor.java
+++ b/java/src/org/openqa/selenium/remote/HttpCommandExecutor.java
@@ -25,6 +25,8 @@
 
 import java.io.IOException;
 import java.net.URL;
+import java.util.Collections;
+import java.util.HashMap;
 import java.util.Map;
 import org.openqa.selenium.NoSuchSessionException;
 import org.openqa.selenium.SessionNotCreatedException;
@@ -109,11 +111,34 @@ public HttpCommandExecutor(
       ClientConfig config,
       HttpClient.Factory httpClientFactory) {
     remoteServer = Require.nonNull("HTTP client configuration", config).baseUrl();
-    this.additionalCommands = Require.nonNull("Additional commands", additionalCommands);
+    this.additionalCommands =
+        new HashMap<>(Require.nonNull("Additional commands", additionalCommands));
     this.httpClientFactory = Require.nonNull("HTTP client factory", httpClientFactory);
     this.client = this.httpClientFactory.createClient(config);
   }
 
+  /**
+   * Returns an immutable view of the additional commands.
+   *
+   * @return an unmodifiable map of additional commands.
+   */
+  public Map<String, CommandInfo> getAdditionalCommands() {
+    return Collections.unmodifiableMap(additionalCommands);
+  }
+
+  /**
+   * Adds or updates additional commands. This method is protected to allow subclasses to define
+   * their commands.
+   *
+   * @param commandName the name of the command to add or update.
+   * @param info the CommandInfo for the command.
+   */
+  protected void addAdditionalCommand(String commandName, CommandInfo info) {
+    Require.nonNull("Command name", commandName);
+    Require.nonNull("Command info", info);
+    this.additionalCommands.put(commandName, info);
+  }
+
   /**
    * It may be useful to extend the commands understood by this {@code HttpCommandExecutor} at run
    * time, and this can be achieved via this method. Note, this is protected, and expected usage is
diff --git a/java/test/org/openqa/selenium/remote/RemoteWebDriverInitializationTest.java b/java/test/org/openqa/selenium/remote/RemoteWebDriverInitializationTest.java
index 111cac68e5085..8c01983488ed3 100644
--- a/java/test/org/openqa/selenium/remote/RemoteWebDriverInitializationTest.java
+++ b/java/test/org/openqa/selenium/remote/RemoteWebDriverInitializationTest.java
@@ -51,6 +51,7 @@
 import org.openqa.selenium.remote.http.ClientConfig;
 import org.openqa.selenium.remote.http.Contents;
 import org.openqa.selenium.remote.http.HttpClient;
+import org.openqa.selenium.remote.http.HttpMethod;
 import org.openqa.selenium.remote.http.HttpResponse;
 
 @Tag("UnitTests")
@@ -234,4 +235,22 @@ public void quit() {
       quitCalled = true;
     }
   }
+
+  @Test
+  void additionalCommandsCanBeModified() throws MalformedURLException {
+    HttpClient client = mock(HttpClient.class);
+    HttpClient.Factory factory = mock(HttpClient.Factory.class);
+
+    when(factory.createClient(any(ClientConfig.class))).thenReturn(client);
+
+    URL url = new URL("http://localhost:4444/");
+    HttpCommandExecutor executor =
+        new HttpCommandExecutor(emptyMap(), ClientConfig.defaultConfig().baseUrl(url), factory);
+
+    String commandName = "customCommand";
+    CommandInfo commandInfo = new CommandInfo("/session/:sessionId/custom", HttpMethod.GET);
+    executor.addAdditionalCommand(commandName, commandInfo);
+
+    assertThat(executor.getAdditionalCommands()).containsEntry(commandName, commandInfo);
+  }
 }