diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/client/McpAsyncClient.java b/mcp-core/src/main/java/io/modelcontextprotocol/client/McpAsyncClient.java
index 3509b760b..232efd465 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/client/McpAsyncClient.java
+++ b/mcp-core/src/main/java/io/modelcontextprotocol/client/McpAsyncClient.java
@@ -13,6 +13,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.function.Function;
 
 import io.modelcontextprotocol.client.LifecycleInitializer.Initialization;
@@ -185,6 +186,13 @@ public class McpAsyncClient {
 
 	private final boolean applyElicitationDefaults;
 
+	/**
+	 * Consumers notified for every logging message received from the server. Held as a
+	 * live reference so that consumers registered after the client was built are picked
+	 * up by the already installed notification handler.
+	 */
+	private final List<Function<LoggingMessageNotification, Mono<Void>>> loggingConsumers;
+
 	/**
 	 * Create a new McpAsyncClient with the given transport and session request-response
 	 * timeout.
@@ -304,11 +312,12 @@ public class McpAsyncClient {
 				asyncPromptsChangeNotificationHandler(promptsChangeConsumersFinal));
 
 		// Utility Logging Notification
-		List<Function<LoggingMessageNotification, Mono<Void>>> loggingConsumersFinal = new ArrayList<>();
+		List<Function<LoggingMessageNotification, Mono<Void>>> loggingConsumersFinal = new CopyOnWriteArrayList<>();
 		loggingConsumersFinal.add((notification) -> Mono.fromRunnable(() -> logger.debug("Logging: {}", notification)));
 		if (!Utils.isEmpty(features.loggingConsumers())) {
 			loggingConsumersFinal.addAll(features.loggingConsumers());
 		}
+		this.loggingConsumers = loggingConsumersFinal;
 		notificationHandlers.put(McpSchema.METHOD_NOTIFICATION_MESSAGE,
 				asyncLoggingNotificationHandler(loggingConsumersFinal));
 
@@ -1103,6 +1112,19 @@ private NotificationHandler asyncLoggingNotificationHandler(
 		};
 	}
 
+	/**
+	 * Registers an additional consumer for logging messages received from the server.
+	 * <p>
+	 * Unlike {@link McpClient.AsyncSpec#loggingConsumer(Function)}, this can be called
+	 * after the client has been built, so a consumer may be registered only once
+	 * {@link #getServerCapabilities()} shows the server supports logging.
+	 * @param loggingConsumer A consumer that receives logging messages. Must not be null.
+	 */
+	public void addLoggingConsumer(Function<LoggingMessageNotification, Mono<Void>> loggingConsumer) {
+		Assert.notNull(loggingConsumer, "Logging consumer must not be null");
+		this.loggingConsumers.add(loggingConsumer);
+	}
+
 	/**
 	 * Sets the minimum logging level for messages received from the server. The client
 	 * will only receive log messages at or above the specified severity level.
diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/client/McpSyncClient.java b/mcp-core/src/main/java/io/modelcontextprotocol/client/McpSyncClient.java
index 7e08f83a0..ee4c05059 100644
--- a/mcp-core/src/main/java/io/modelcontextprotocol/client/McpSyncClient.java
+++ b/mcp-core/src/main/java/io/modelcontextprotocol/client/McpSyncClient.java
@@ -6,6 +6,7 @@
 
 import java.time.Duration;
 import java.util.Map;
+import java.util.function.Consumer;
 import java.util.function.Supplier;
 
 import org.slf4j.Logger;
@@ -19,6 +20,7 @@
 import io.modelcontextprotocol.spec.McpSchema.ListPromptsResult;
 import io.modelcontextprotocol.util.Assert;
 import reactor.core.publisher.Mono;
+import reactor.core.scheduler.Schedulers;
 
 /**
  * A synchronous client implementation for the Model Context Protocol (MCP) that wraps an
@@ -423,6 +425,20 @@ public GetPromptResult getPrompt(GetPromptRequest getPromptRequest) {
 		return withProvidedContext(this.delegate.getPrompt(getPromptRequest)).block();
 	}
 
+	/**
+	 * Registers an additional consumer for logging messages received from the server.
+	 * <p>
+	 * Unlike {@link McpClient.SyncSpec#loggingConsumer(Consumer)}, this can be called
+	 * after the client has been built, so a consumer may be registered only once
+	 * {@link #getServerCapabilities()} reports that the server supports logging.
+	 * @param loggingConsumer the consumer that receives logging messages
+	 */
+	public void addLoggingConsumer(Consumer<McpSchema.LoggingMessageNotification> loggingConsumer) {
+		Assert.notNull(loggingConsumer, "Logging consumer must not be null");
+		this.delegate.addLoggingConsumer(
+				l -> Mono.<Void>fromRunnable(() -> loggingConsumer.accept(l)).subscribeOn(Schedulers.boundedElastic()));
+	}
+
 	/**
 	 * Client can set the minimum logging level it wants to receive from the server.
 	 * @param loggingLevel the min logging level
diff --git a/mcp-core/src/test/java/io/modelcontextprotocol/client/McpAsyncClientTest.java b/mcp-core/src/test/java/io/modelcontextprotocol/client/McpAsyncClientTest.java
index dea7d42e9..73aa0bd1e 100644
--- a/mcp-core/src/test/java/io/modelcontextprotocol/client/McpAsyncClientTest.java
+++ b/mcp-core/src/test/java/io/modelcontextprotocol/client/McpAsyncClientTest.java
@@ -106,6 +106,31 @@ void bothHandlersPresent() {
 
 		}
 
+		@Nested
+		class LoggingConsumers {
+
+			@Test
+			void addLoggingConsumerAfterBuild() {
+				McpClientTransport transport = mock(McpClientTransport.class);
+				when(transport.protocolVersions()).thenReturn(List.of("2024-11-05"));
+				var client = McpClient.async(transport).jsonSchemaValidator(mock(JsonSchemaValidator.class)).build();
+
+				assertThatCode(() -> client.addLoggingConsumer(notification -> Mono.empty()))
+					.doesNotThrowAnyException();
+			}
+
+			@Test
+			void addLoggingConsumerRejectsNull() {
+				McpClientTransport transport = mock(McpClientTransport.class);
+				when(transport.protocolVersions()).thenReturn(List.of("2024-11-05"));
+				var client = McpClient.async(transport).jsonSchemaValidator(mock(JsonSchemaValidator.class)).build();
+
+				assertThatThrownBy(() -> client.addLoggingConsumer(null)).isInstanceOf(IllegalArgumentException.class)
+					.hasMessage("Logging consumer must not be null");
+			}
+
+		}
+
 		@Nested
 		class ClientCapabilities {