diff --git a/tempest-testing-docker/src/main/kotlin/app/cash/tempest/testing/DockerDynamoDbServer.kt b/tempest-testing-docker/src/main/kotlin/app/cash/tempest/testing/DockerDynamoDbServer.kt
index 86291e674..4b95d8eab 100644
--- a/tempest-testing-docker/src/main/kotlin/app/cash/tempest/testing/DockerDynamoDbServer.kt
+++ b/tempest-testing-docker/src/main/kotlin/app/cash/tempest/testing/DockerDynamoDbServer.kt
@@ -70,6 +70,7 @@ class DockerDynamoDbServer private constructor(
   )
 
   object Factory : TestDynamoDbServer.Factory<DockerDynamoDbServer> {
+    override fun hostName(port: Int): String = app.cash.tempest.testing.internal.hostName(port)
     override fun create(port: Int, onBeforeStartup: () -> Unit) = DockerDynamoDbServer(port, onBeforeStartup)
   }
 }
diff --git a/tempest-testing-internal/src/main/kotlin/app/cash/tempest/testing/internal/DefaultTestDynamoDbClient.kt b/tempest-testing-internal/src/main/kotlin/app/cash/tempest/testing/internal/DefaultTestDynamoDbClient.kt
index 3fdc09390..f3c6ac742 100644
--- a/tempest-testing-internal/src/main/kotlin/app/cash/tempest/testing/internal/DefaultTestDynamoDbClient.kt
+++ b/tempest-testing-internal/src/main/kotlin/app/cash/tempest/testing/internal/DefaultTestDynamoDbClient.kt
@@ -22,14 +22,12 @@ import com.google.common.util.concurrent.AbstractIdleService
 
 class DefaultTestDynamoDbClient(
   override val tables: List<TestTable>,
+  private val hostName: String,
   private val port: Int,
 ) : AbstractIdleService(), TestDynamoDbClient {
-  // Lazy so that hostName is resolved after the DynamoDB Local server is started,
-  // not at construction time when the placeholder ServerSocket is still holding the port.
-  private val hostName by lazy { hostName(port) }
 
-  override val dynamoDb by lazy { buildDynamoDb(hostName, port) }
-  override val dynamoDbStreams by lazy { buildDynamoDbStreams(hostName, port) }
+  override val dynamoDb = buildDynamoDb(hostName, port)
+  override val dynamoDbStreams = buildDynamoDbStreams(hostName, port)
 
   override fun startUp() {
     reset()
diff --git a/tempest-testing-internal/src/main/kotlin/app/cash/tempest/testing/internal/TestDynamoDbService.kt b/tempest-testing-internal/src/main/kotlin/app/cash/tempest/testing/internal/TestDynamoDbService.kt
index bad67045a..a07c0de64 100644
--- a/tempest-testing-internal/src/main/kotlin/app/cash/tempest/testing/internal/TestDynamoDbService.kt
+++ b/tempest-testing-internal/src/main/kotlin/app/cash/tempest/testing/internal/TestDynamoDbService.kt
@@ -75,7 +75,7 @@ class TestDynamoDbService private constructor(
     ): TestDynamoDbService {
       val portHolder = port?.let { PortHolder(it) } ?: defaultPortHolder(serverFactory.toString())
       return TestDynamoDbService(
-        DefaultTestDynamoDbClient(tables, portHolder.value),
+        DefaultTestDynamoDbClient(tables, serverFactory.hostName(portHolder.value), portHolder.value),
         serverFactory.create(portHolder.value, portHolder.releasePort)
       )
     }
diff --git a/tempest-testing-jvm/src/main/kotlin/app/cash/tempest/testing/JvmDynamoDbServer.kt b/tempest-testing-jvm/src/main/kotlin/app/cash/tempest/testing/JvmDynamoDbServer.kt
index e396dd77b..6f5064836 100644
--- a/tempest-testing-jvm/src/main/kotlin/app/cash/tempest/testing/JvmDynamoDbServer.kt
+++ b/tempest-testing-jvm/src/main/kotlin/app/cash/tempest/testing/JvmDynamoDbServer.kt
@@ -73,6 +73,7 @@ class JvmDynamoDbServer private constructor(
   }
 
   object Factory : TestDynamoDbServer.Factory<JvmDynamoDbServer> {
+    override fun hostName(port: Int) = "localhost"
     override fun create(port: Int, onBeforeStartup: () -> Unit) = JvmDynamoDbServer(port, onBeforeStartup)
   }
 }
diff --git a/tempest-testing/src/main/kotlin/app/cash/tempest/testing/TestDynamoDbServer.kt b/tempest-testing/src/main/kotlin/app/cash/tempest/testing/TestDynamoDbServer.kt
index b9bd828c4..443b0efcf 100644
--- a/tempest-testing/src/main/kotlin/app/cash/tempest/testing/TestDynamoDbServer.kt
+++ b/tempest-testing/src/main/kotlin/app/cash/tempest/testing/TestDynamoDbServer.kt
@@ -26,6 +26,8 @@ interface TestDynamoDbServer : Service {
   val port: Int
 
   interface Factory<T : TestDynamoDbServer> {
+    /** The hostname the client should use to connect to the server. */
+    fun hostName(port: Int): String
     fun create(port: Int): T = create(port) {}
     fun create(port: Int, onBeforeStartup: () -> Unit): T
   }
diff --git a/tempest2-testing-docker/src/main/kotlin/app/cash/tempest2/testing/DockerDynamoDbServer.kt b/tempest2-testing-docker/src/main/kotlin/app/cash/tempest2/testing/DockerDynamoDbServer.kt
index 2ba8d17f7..c5f342fb9 100644
--- a/tempest2-testing-docker/src/main/kotlin/app/cash/tempest2/testing/DockerDynamoDbServer.kt
+++ b/tempest2-testing-docker/src/main/kotlin/app/cash/tempest2/testing/DockerDynamoDbServer.kt
@@ -17,6 +17,7 @@
 package app.cash.tempest2.testing
 
 import app.cash.tempest2.testing.internal.buildDynamoDb
+import app.cash.tempest2.testing.internal.hostName
 import com.github.dockerjava.api.model.ExposedPort
 import com.github.dockerjava.api.model.Ports
 import com.google.common.util.concurrent.AbstractIdleService
@@ -69,6 +70,7 @@ class DockerDynamoDbServer private constructor(
   )
 
   object Factory : TestDynamoDbServer.Factory<DockerDynamoDbServer> {
+    override fun hostName(port: Int): String = app.cash.tempest2.testing.internal.hostName(port)
     override fun create(port: Int, onBeforeStartup: () -> Unit) = DockerDynamoDbServer(port, onBeforeStartup)
   }
 }
diff --git a/tempest2-testing-internal/src/main/kotlin/app/cash/tempest2/testing/internal/DefaultTestDynamoDbClient.kt b/tempest2-testing-internal/src/main/kotlin/app/cash/tempest2/testing/internal/DefaultTestDynamoDbClient.kt
index cc187aaab..b2fbe457f 100644
--- a/tempest2-testing-internal/src/main/kotlin/app/cash/tempest2/testing/internal/DefaultTestDynamoDbClient.kt
+++ b/tempest2-testing-internal/src/main/kotlin/app/cash/tempest2/testing/internal/DefaultTestDynamoDbClient.kt
@@ -23,16 +23,14 @@ import software.amazon.awssdk.services.dynamodb.model.DeleteTableRequest
 
 class DefaultTestDynamoDbClient(
   override val tables: List<TestTable>,
+  private val hostName: String,
   private val port: Int,
 ) : AbstractIdleService(), TestDynamoDbClient {
-  // Lazy so that hostName is resolved after the DynamoDB Local server is started,
-  // not at construction time when the placeholder ServerSocket is still holding the port.
-  private val hostName by lazy { hostName(port) }
 
-  override val dynamoDb by lazy { buildDynamoDb(hostName, port) }
-  override val asyncDynamoDb by lazy { buildAsyncDynamoDb(hostName, port) }
-  override val dynamoDbStreams by lazy { buildDynamoDbStreams(hostName, port) }
-  override val asyncDynamoDbStreams by lazy { buildAsyncDynamoDbStreams(hostName, port) }
+  override val dynamoDb = buildDynamoDb(hostName, port)
+  override val asyncDynamoDb = buildAsyncDynamoDb(hostName, port)
+  override val dynamoDbStreams = buildDynamoDbStreams(hostName, port)
+  override val asyncDynamoDbStreams = buildAsyncDynamoDbStreams(hostName, port)
 
   override fun startUp() {
     reset()
diff --git a/tempest2-testing-internal/src/main/kotlin/app/cash/tempest2/testing/internal/TestDynamoDbService.kt b/tempest2-testing-internal/src/main/kotlin/app/cash/tempest2/testing/internal/TestDynamoDbService.kt
index 55223c464..db11902ea 100644
--- a/tempest2-testing-internal/src/main/kotlin/app/cash/tempest2/testing/internal/TestDynamoDbService.kt
+++ b/tempest2-testing-internal/src/main/kotlin/app/cash/tempest2/testing/internal/TestDynamoDbService.kt
@@ -75,7 +75,7 @@ class TestDynamoDbService(
     ): TestDynamoDbService {
       val portHolder = port?.let { PortHolder(it) } ?: defaultPortHolder(serverFactory.toString())
       return TestDynamoDbService(
-        DefaultTestDynamoDbClient(tables, portHolder.value),
+        DefaultTestDynamoDbClient(tables, serverFactory.hostName(portHolder.value), portHolder.value),
         serverFactory.create(portHolder.value, portHolder.releasePort)
       )
     }
diff --git a/tempest2-testing-jvm/src/main/kotlin/app/cash/tempest2/testing/JvmDynamoDbServer.kt b/tempest2-testing-jvm/src/main/kotlin/app/cash/tempest2/testing/JvmDynamoDbServer.kt
index 7b649f1c9..a22564271 100644
--- a/tempest2-testing-jvm/src/main/kotlin/app/cash/tempest2/testing/JvmDynamoDbServer.kt
+++ b/tempest2-testing-jvm/src/main/kotlin/app/cash/tempest2/testing/JvmDynamoDbServer.kt
@@ -73,6 +73,7 @@ class JvmDynamoDbServer private constructor(
   }
 
   object Factory : TestDynamoDbServer.Factory<JvmDynamoDbServer> {
+    override fun hostName(port: Int) = "localhost"
     override fun create(port: Int, onBeforeStartup: () -> Unit) = JvmDynamoDbServer(port, onBeforeStartup)
   }
 }
diff --git a/tempest2-testing/src/main/kotlin/app/cash/tempest2/testing/TestDynamoDbServer.kt b/tempest2-testing/src/main/kotlin/app/cash/tempest2/testing/TestDynamoDbServer.kt
index bcf261c3f..8d4d4d23b 100644
--- a/tempest2-testing/src/main/kotlin/app/cash/tempest2/testing/TestDynamoDbServer.kt
+++ b/tempest2-testing/src/main/kotlin/app/cash/tempest2/testing/TestDynamoDbServer.kt
@@ -26,6 +26,8 @@ interface TestDynamoDbServer : Service {
   val port: Int
 
   interface Factory<T : TestDynamoDbServer> {
+    /** The hostname the client should use to connect to the server. */
+    fun hostName(port: Int): String
     fun create(port: Int): T = create(port) {}
     fun create(port: Int, onBeforeStartup: () -> Unit): T
   }