diff --git a/module/spring-boot-mongodb/src/main/java/org/springframework/boot/mongodb/docker/compose/MongoDockerComposeConnectionDetailsFactory.java b/module/spring-boot-mongodb/src/main/java/org/springframework/boot/mongodb/docker/compose/MongoDockerComposeConnectionDetailsFactory.java
index 407f45c8911..fe00b70a3c9 100644
--- a/module/spring-boot-mongodb/src/main/java/org/springframework/boot/mongodb/docker/compose/MongoDockerComposeConnectionDetailsFactory.java
+++ b/module/spring-boot-mongodb/src/main/java/org/springframework/boot/mongodb/docker/compose/MongoDockerComposeConnectionDetailsFactory.java
@@ -16,6 +16,9 @@
 
 package org.springframework.boot.mongodb.docker.compose;
 
+import java.net.URLEncoder;
+import java.nio.charset.StandardCharsets;
+
 import com.mongodb.ConnectionString;
 import org.jspecify.annotations.Nullable;
 
@@ -69,9 +72,9 @@ class MongoDockerComposeConnectionDetailsFactory extends DockerComposeConnection
 			MongoEnvironment environment = new MongoEnvironment(service.env());
 			StringBuilder builder = new StringBuilder("mongodb://");
 			if (environment.getUsername() != null) {
-				builder.append(environment.getUsername());
+				builder.append(encode(environment.getUsername()));
 				builder.append(":");
-				builder.append((environment.getPassword() != null) ? environment.getPassword() : "");
+				builder.append((environment.getPassword() != null) ? encode(environment.getPassword()) : "");
 				builder.append("@");
 			}
 			builder.append(service.host());
@@ -85,6 +88,10 @@ class MongoDockerComposeConnectionDetailsFactory extends DockerComposeConnection
 			return new ConnectionString(builder.toString());
 		}
 
+		private static String encode(String input) {
+			return URLEncoder.encode(input, StandardCharsets.UTF_8).replace("+", "%20");
+		}
+
 		@Override
 		public @Nullable SslBundle getSslBundle() {
 			return this.sslBundle;
diff --git a/module/spring-boot-mongodb/src/test/java/org/springframework/boot/mongodb/docker/compose/MongoDockerComposeConnectionDetailsFactoryTests.java b/module/spring-boot-mongodb/src/test/java/org/springframework/boot/mongodb/docker/compose/MongoDockerComposeConnectionDetailsFactoryTests.java
new file mode 100644
index 00000000000..5f952fde18f
--- /dev/null
+++ b/module/spring-boot-mongodb/src/test/java/org/springframework/boot/mongodb/docker/compose/MongoDockerComposeConnectionDetailsFactoryTests.java
@@ -0,0 +1,94 @@
+/*
+ * Copyright 2012-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.mongodb.docker.compose;
+
+import java.util.Collections;
+import java.util.Map;
+
+import com.mongodb.ConnectionString;
+import com.mongodb.MongoCredential;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.docker.compose.core.ConnectionPorts;
+import org.springframework.boot.docker.compose.core.RunningService;
+import org.springframework.boot.mongodb.docker.compose.MongoDockerComposeConnectionDetailsFactory.MongoDockerComposeConnectionDetails;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link MongoDockerComposeConnectionDetailsFactory}.
+ *
+ * @author Iram Tazim Hoque
+ */
+class MongoDockerComposeConnectionDetailsFactoryTests {
+
+	@Test
+	void createConnectionDetails() {
+		RunningService runningService = mockRunningService();
+		given(runningService.env()).willReturn(Map.of("MONGO_INITDB_ROOT_USERNAME", "root",
+				"MONGO_INITDB_ROOT_PASSWORD", "secret", "MONGO_INITDB_DATABASE", "mydatabase"));
+		ConnectionString connectionString = new MongoDockerComposeConnectionDetails(runningService)
+			.getConnectionString();
+		assertThat(connectionString.getHosts()).containsExactly("localhost:30001");
+		assertThat(connectionString.getDatabase()).isEqualTo("mydatabase");
+		MongoCredential credential = connectionString.getCredential();
+		assertThat(credential).isNotNull();
+		assertThat(credential.getUserName()).isEqualTo("root");
+		assertThat(credential.getPassword()).isEqualTo("secret".toCharArray());
+		assertThat(credential.getSource()).isEqualTo("admin");
+	}
+
+	@Test
+	void createConnectionDetailsWhenCredentialsContainReservedCharacters() {
+		RunningService runningService = mockRunningService();
+		given(runningService.env()).willReturn(Map.of("MONGO_INITDB_ROOT_USERNAME", "us@r:name",
+				"MONGO_INITDB_ROOT_PASSWORD", "p@ss:w/rd%?#[] +", "MONGO_INITDB_DATABASE", "mydatabase"));
+		ConnectionString connectionString = new MongoDockerComposeConnectionDetails(runningService)
+			.getConnectionString();
+		assertThat(connectionString.getHosts()).containsExactly("localhost:30001");
+		assertThat(connectionString.getDatabase()).isEqualTo("mydatabase");
+		MongoCredential credential = connectionString.getCredential();
+		assertThat(credential).isNotNull();
+		assertThat(credential.getUserName()).isEqualTo("us@r:name");
+		assertThat(credential.getPassword()).isEqualTo("p@ss:w/rd%?#[] +".toCharArray());
+		assertThat(credential.getSource()).isEqualTo("admin");
+	}
+
+	@Test
+	void createConnectionDetailsWithoutCredentials() {
+		RunningService runningService = mockRunningService();
+		given(runningService.env()).willReturn(Collections.emptyMap());
+		ConnectionString connectionString = new MongoDockerComposeConnectionDetails(runningService)
+			.getConnectionString();
+		assertThat(connectionString.getHosts()).containsExactly("localhost:30001");
+		assertThat(connectionString.getDatabase()).isEqualTo("test");
+		assertThat(connectionString.getCredential()).isNull();
+	}
+
+	private static RunningService mockRunningService() {
+		RunningService service = mock(RunningService.class);
+		given(service.labels()).willReturn(Collections.emptyMap());
+		ConnectionPorts connectionPorts = mock(ConnectionPorts.class);
+		given(service.ports()).willReturn(connectionPorts);
+		given(service.host()).willReturn("localhost");
+		given(connectionPorts.get(27017)).willReturn(30001);
+		return service;
+	}
+
+}