diff --git a/akka-io/src/main/scala/akka/io/Tcp.scala b/akka-io/src/main/scala/akka/io/Tcp.scala
index e9b7a07409..c1873e91e5 100644
--- a/akka-io/src/main/scala/akka/io/Tcp.scala
+++ b/akka-io/src/main/scala/akka/io/Tcp.scala
@@ -132,11 +132,11 @@ object Tcp extends ExtensionKey[TcpExt] {
 
   case class Connect(remoteAddress: InetSocketAddress,
                      localAddress: Option[InetSocketAddress] = None,
-                     options: Traversable[SocketOption] = Nil) extends Command
+                     options: immutable.Traversable[SocketOption] = Nil) extends Command
   case class Bind(handler: ActorRef,
                   endpoint: InetSocketAddress,
                   backlog: Int = 100,
-                  options: Traversable[SocketOption] = Nil) extends Command
+                  options: immutable.Traversable[SocketOption] = Nil) extends Command
   case class Register(handler: ActorRef) extends Command
   case object Unbind extends Command
 
diff --git a/akka-io/src/main/scala/akka/io/TcpConnection.scala b/akka-io/src/main/scala/akka/io/TcpConnection.scala
index 3dc9e6958c..7031021191 100644
--- a/akka-io/src/main/scala/akka/io/TcpConnection.scala
+++ b/akka-io/src/main/scala/akka/io/TcpConnection.scala
@@ -9,6 +9,7 @@ import java.io.IOException
 import java.nio.channels.SocketChannel
 import java.nio.ByteBuffer
 import scala.annotation.tailrec
+import scala.collection.immutable
 import scala.util.control.NonFatal
 import scala.concurrent.duration._
 import akka.actor._
@@ -102,7 +103,7 @@ private[io] abstract class TcpConnection(val channel: SocketChannel,
   // AUXILIARIES and IMPLEMENTATION
 
   /** used in subclasses to start the common machinery above once a channel is connected */
-  def completeConnect(commander: ActorRef, options: Traversable[SocketOption]): Unit = {
+  def completeConnect(commander: ActorRef, options: immutable.Traversable[SocketOption]): Unit = {
     options.foreach(_.afterConnect(channel.socket))
 
     commander ! Connected(
diff --git a/akka-io/src/main/scala/akka/io/TcpIncomingConnection.scala b/akka-io/src/main/scala/akka/io/TcpIncomingConnection.scala
index a4dc447a5d..1036509b4e 100644
--- a/akka-io/src/main/scala/akka/io/TcpIncomingConnection.scala
+++ b/akka-io/src/main/scala/akka/io/TcpIncomingConnection.scala
@@ -5,6 +5,7 @@
 package akka.io
 
 import java.nio.channels.SocketChannel
+import scala.collection.immutable
 import akka.actor.ActorRef
 import Tcp.SocketOption
 
@@ -15,7 +16,7 @@ import Tcp.SocketOption
 private[io] class TcpIncomingConnection(_channel: SocketChannel,
                                         _tcp: TcpExt,
                                         handler: ActorRef,
-                                        options: Traversable[SocketOption])
+                                        options: immutable.Traversable[SocketOption])
   extends TcpConnection(_channel, _tcp) {
 
   context.watch(handler) // sign death pact
diff --git a/akka-io/src/main/scala/akka/io/TcpListener.scala b/akka-io/src/main/scala/akka/io/TcpListener.scala
index 198905f684..c510f1c186 100644
--- a/akka-io/src/main/scala/akka/io/TcpListener.scala
+++ b/akka-io/src/main/scala/akka/io/TcpListener.scala
@@ -7,6 +7,7 @@ package akka.io
 import java.net.InetSocketAddress
 import java.nio.channels.ServerSocketChannel
 import scala.annotation.tailrec
+import scala.collection.immutable
 import scala.util.control.NonFatal
 import akka.actor.{ ActorLogging, ActorRef, Actor }
 import TcpSelector._
@@ -17,7 +18,7 @@ private[io] class TcpListener(handler: ActorRef,
                               backlog: Int,
                               bindCommander: ActorRef,
                               settings: TcpExt#Settings,
-                              options: Traversable[SocketOption]) extends Actor with ActorLogging {
+                              options: immutable.Traversable[SocketOption]) extends Actor with ActorLogging {
 
   def selector: ActorRef = context.parent
 
diff --git a/akka-io/src/main/scala/akka/io/TcpOutgoingConnection.scala b/akka-io/src/main/scala/akka/io/TcpOutgoingConnection.scala
index e71b734561..040d866e5b 100644
--- a/akka-io/src/main/scala/akka/io/TcpOutgoingConnection.scala
+++ b/akka-io/src/main/scala/akka/io/TcpOutgoingConnection.scala
@@ -7,6 +7,7 @@ package akka.io
 import java.net.InetSocketAddress
 import java.io.IOException
 import java.nio.channels.SocketChannel
+import scala.collection.immutable
 import akka.actor.ActorRef
 import TcpSelector._
 import Tcp._
@@ -19,7 +20,7 @@ private[io] class TcpOutgoingConnection(_tcp: TcpExt,
                                         commander: ActorRef,
                                         remoteAddress: InetSocketAddress,
                                         localAddress: Option[InetSocketAddress],
-                                        options: Traversable[SocketOption])
+                                        options: immutable.Traversable[SocketOption])
   extends TcpConnection(TcpOutgoingConnection.newSocketChannel(), _tcp) {
 
   context.watch(commander) // sign death pact
@@ -37,7 +38,7 @@ private[io] class TcpOutgoingConnection(_tcp: TcpExt,
 
   def receive: Receive = PartialFunction.empty
 
-  def connecting(commander: ActorRef, options: Traversable[SocketOption]): Receive = {
+  def connecting(commander: ActorRef, options: immutable.Traversable[SocketOption]): Receive = {
     case ChannelConnectable ⇒
       try {
         val connected = channel.finishConnect()
diff --git a/akka-io/src/main/scala/akka/io/TcpSelector.scala b/akka-io/src/main/scala/akka/io/TcpSelector.scala
index 6e1b2e1c99..580a7c02d0 100644
--- a/akka-io/src/main/scala/akka/io/TcpSelector.scala
+++ b/akka-io/src/main/scala/akka/io/TcpSelector.scala
@@ -9,7 +9,8 @@ import java.nio.channels.spi.SelectorProvider
 import java.nio.channels.{ ServerSocketChannel, SelectionKey, SocketChannel }
 import java.nio.channels.SelectionKey._
 import scala.util.control.NonFatal
-import scala.collection.immutable.HashMap
+import scala.collection.immutable
+import immutable.HashMap
 import scala.concurrent.duration._
 import akka.actor._
 import Tcp._
@@ -229,7 +230,7 @@ private[io] object TcpSelector {
   case class RegisterOutgoingConnection(channel: SocketChannel)
   case class RegisterServerSocketChannel(channel: ServerSocketChannel)
   case class RegisterIncomingConnection(channel: SocketChannel, handler: ActorRef,
-                                        options: Traversable[SocketOption]) extends Tcp.Command
+                                        options: immutable.Traversable[SocketOption]) extends Tcp.Command
   case class Retry(command: Command, retriesLeft: Int) { require(retriesLeft >= 0) }
 
   case object ChannelConnectable
diff --git a/akka-io/src/test/scala/akka/io/IntegrationSpecSupport.scala b/akka-io/src/test/scala/akka/io/IntegrationSpecSupport.scala
index ea93b7809a..0feeb3809f 100644
--- a/akka-io/src/test/scala/akka/io/IntegrationSpecSupport.scala
+++ b/akka-io/src/test/scala/akka/io/IntegrationSpecSupport.scala
@@ -7,6 +7,7 @@ package akka.io
 import scala.annotation.tailrec
 import akka.testkit.{ AkkaSpec, TestProbe }
 import akka.actor.ActorRef
+import scala.collection.immutable
 import Tcp._
 import TestUtils._
 
@@ -45,10 +46,10 @@ trait IntegrationSpecSupport { _: AkkaSpec ⇒
       }
 
     /** allow overriding socket options for server side channel */
-    def bindOptions: Traversable[SocketOption] = Nil
+    def bindOptions: immutable.Traversable[SocketOption] = Nil
 
     /** allow overriding socket options for client side channel */
-    def connectOptions: Traversable[SocketOption] = Nil
+    def connectOptions: immutable.Traversable[SocketOption] = Nil
   }
 
 }