diff --git a/gcloud-java-translate/src/main/java/com/google/cloud/translate/Option.java b/gcloud-java-translate/src/main/java/com/google/cloud/translate/Option.java
new file mode 100644
index 000000000000..7fc05678e39e
--- /dev/null
+++ b/gcloud-java-translate/src/main/java/com/google/cloud/translate/Option.java
@@ -0,0 +1,72 @@
+/*
+ * Copyright 2016 Google Inc. All Rights Reserved.
+ *
+ * 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
+ *
+ *       http://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 com.google.cloud.translate;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import com.google.cloud.translate.spi.TranslateRpc;
+import com.google.common.base.MoreObjects;
+
+import java.io.Serializable;
+import java.util.Objects;
+
+/**
+ * Base class for Translate operation option.
+ */
+abstract class Option implements Serializable {
+
+  private static final long serialVersionUID = 8546712558603322394L;
+
+  private final TranslateRpc.Option rpcOption;
+  private final Object value;
+
+  Option(TranslateRpc.Option rpcOption, Object value) {
+    this.rpcOption = checkNotNull(rpcOption);
+    this.value = value;
+  }
+
+  TranslateRpc.Option rpcOption() {
+    return rpcOption;
+  }
+
+  Object value() {
+    return value;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (!(obj instanceof Option)) {
+      return false;
+    }
+    Option other = (Option) obj;
+    return Objects.equals(rpcOption, other.rpcOption)
+        && Objects.equals(value, other.value);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(rpcOption, value);
+  }
+
+  @Override
+  public String toString() {
+    return MoreObjects.toStringHelper(this)
+        .add("name", rpcOption.value())
+        .add("value", value)
+        .toString();
+  }
+}
diff --git a/gcloud-java-translate/src/main/java/com/google/cloud/translate/Translate.java b/gcloud-java-translate/src/main/java/com/google/cloud/translate/Translate.java
index 1b1a3b9b12be..1d661a978794 100644
--- a/gcloud-java-translate/src/main/java/com/google/cloud/translate/Translate.java
+++ b/gcloud-java-translate/src/main/java/com/google/cloud/translate/Translate.java
@@ -17,6 +17,9 @@
 package com.google.cloud.translate;
 
 import com.google.cloud.Service;
+import com.google.cloud.translate.spi.TranslateRpc;
+
+import java.util.List;
 
 /**
  * An interface for Google Translate.
@@ -24,4 +27,47 @@
  * @see <a href="https://cloud.google.com/translate/docs">Google Translate</a>
  */
 public interface Translate extends Service<TranslateOptions> {
+
+  /**
+   * Class for specifying supported language listing options.
+   */
+  class LanguageListOption extends Option {
+
+    private static final long serialVersionUID = 1982978040516658597L;
+
+    private LanguageListOption(TranslateRpc.Option rpcOption, String value) {
+      super(rpcOption, value);
+    }
+
+    /**
+     * Returns an option for setting the target language. If this option is not provided, the value
+     * returned by {@link TranslateOptions#targetLanguage()} is used. When provided, the returned
+     * {@link Language#name()} will be in the language specified by the {@code targetLanguage} code.
+     *
+     * @param targetLanguage the target language code
+     */
+    public static LanguageListOption targetLanguage(String targetLanguage) {
+      return new LanguageListOption(TranslateRpc.Option.TARGET_LANGUAGE, targetLanguage);
+    }
+  }
+
+  /**
+   * Returns the list of languages supported by Google Translate. If
+   * {@link LanguageListOption#targetLanguage(String)} is provided, {@link Language#name()} values
+   * are localized according to the provided target language. If no such option is passed,
+   * {@link Language#name()} values are localized according to
+   * {@link TranslateOptions#targetLanguage()}.
+   *
+   * <p>Example of listing supported languages, localized according to
+   * {@link TranslateOptions#targetLanguage()}:
+   * <pre> {@code
+   * List<Language> languages = translate.listSupportedLanguages();
+   * }</pre>
+   * Or according to another target language:
+   * <pre> {@code
+   * List<Language> languages = translate.listSupportedLanguages(
+   *     LanguageListOption.targetLanguage("es"));
+   * }</pre>
+   */
+  List<Language> listSupportedLanguages(LanguageListOption... options);
 }
diff --git a/gcloud-java-translate/src/main/java/com/google/cloud/translate/TranslateImpl.java b/gcloud-java-translate/src/main/java/com/google/cloud/translate/TranslateImpl.java
new file mode 100644
index 000000000000..36d0b3afc863
--- /dev/null
+++ b/gcloud-java-translate/src/main/java/com/google/cloud/translate/TranslateImpl.java
@@ -0,0 +1,64 @@
+/*
+ * Copyright 2016 Google Inc. All Rights Reserved.
+ *
+ * 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
+ *
+ *       http://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 com.google.cloud.translate;
+
+import static com.google.cloud.RetryHelper.runWithRetries;
+import static com.google.common.base.Preconditions.checkArgument;
+
+import com.google.api.services.translate.model.LanguagesResource;
+import com.google.cloud.BaseService;
+import com.google.cloud.RetryHelper.RetryHelperException;
+import com.google.cloud.translate.spi.TranslateRpc;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
+
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.Callable;
+
+final class TranslateImpl extends BaseService<TranslateOptions> implements Translate {
+
+  private final TranslateRpc translateRpc;
+
+  TranslateImpl(TranslateOptions options) {
+    super(options);
+    translateRpc = options.rpc();
+  }
+
+  @Override
+  public List<Language> listSupportedLanguages(final LanguageListOption... options) {
+    try {
+      return Lists.transform(runWithRetries(new Callable<List<LanguagesResource>>() {
+        @Override
+        public List<LanguagesResource> call() {
+          return translateRpc.listSupportedLanguages(optionMap(options));
+        }
+      }, options().retryParams(), EXCEPTION_HANDLER, options().clock()), Language.FROM_PB_FUNCTION);
+    } catch (RetryHelperException e) {
+      throw TranslateException.translateAndThrow(e);
+    }
+  }
+
+  private Map<TranslateRpc.Option, ?> optionMap(Option... options) {
+    Map<TranslateRpc.Option, Object> optionMap = Maps.newEnumMap(TranslateRpc.Option.class);
+    for (Option option : options) {
+      Object prev = optionMap.put(option.rpcOption(), option.value());
+      checkArgument(prev == null, "Duplicate option %s", option);
+    }
+    return optionMap;
+  }
+}
diff --git a/gcloud-java-translate/src/main/java/com/google/cloud/translate/TranslateOptions.java b/gcloud-java-translate/src/main/java/com/google/cloud/translate/TranslateOptions.java
index 599d4a1d389f..42d6e200b823 100644
--- a/gcloud-java-translate/src/main/java/com/google/cloud/translate/TranslateOptions.java
+++ b/gcloud-java-translate/src/main/java/com/google/cloud/translate/TranslateOptions.java
@@ -43,9 +43,7 @@ public static class DefaultTranslateFactory implements TranslateFactory {
 
     @Override
     public Translate create(TranslateOptions options) {
-      return null;
-      // todo(mziccard) uncomment as soon as TranslateImpl is implemented
-      // return new TranslateImpl(options);
+      return new TranslateImpl(options);
     }
   }
 
@@ -174,7 +172,13 @@ public int hashCode() {
 
   @Override
   public boolean equals(Object obj) {
-    return obj instanceof TranslateOptions && baseEquals((TranslateOptions) obj);
+    if (!(obj instanceof TranslateOptions)) {
+      return false;
+    }
+    TranslateOptions options = (TranslateOptions) obj;
+    return baseEquals(options)
+        && apiKey.equals(options.apiKey)
+        && targetLanguage.equals(options.targetLanguage);
   }
 
   /**
diff --git a/gcloud-java-translate/src/test/java/com/google/cloud/translate/OptionTest.java b/gcloud-java-translate/src/test/java/com/google/cloud/translate/OptionTest.java
new file mode 100644
index 000000000000..152e5c10c455
--- /dev/null
+++ b/gcloud-java-translate/src/test/java/com/google/cloud/translate/OptionTest.java
@@ -0,0 +1,62 @@
+/*
+ * Copyright 2016 Google Inc. All Rights Reserved.
+ *
+ * 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
+ *
+ *       http://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 com.google.cloud.translate;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertNull;
+
+import com.google.cloud.translate.spi.TranslateRpc;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+public class OptionTest {
+
+  private static final TranslateRpc.Option RPC_OPTION = TranslateRpc.Option.SOURCE_LANGUAGE;
+  private static final String VALUE = "some value";
+  private static final String OTHER_VALUE = "another value";
+  private static final Option OPTION = new Option(RPC_OPTION, VALUE) {};
+  private static final Option OPTION_EQUALS = new Option(RPC_OPTION, VALUE) {};
+  private static final Option OPTION_NOT_EQUALS = new Option(RPC_OPTION, OTHER_VALUE) {};
+
+  @Rule
+  public ExpectedException thrown = ExpectedException.none();
+
+  @Test
+  public void testEquals() {
+    assertEquals(OPTION, OPTION_EQUALS);
+    assertNotEquals(OPTION, OPTION_NOT_EQUALS);
+  }
+
+  @Test
+  public void testHashCode() {
+    assertEquals(OPTION.hashCode(), OPTION_EQUALS.hashCode());
+  }
+
+  @Test
+  public void testConstructor() {
+    assertEquals(RPC_OPTION, OPTION.rpcOption());
+    assertEquals(VALUE, OPTION.value());
+    Option option = new Option(RPC_OPTION, null) {};
+    assertEquals(RPC_OPTION, option.rpcOption());
+    assertNull(option.value());
+    thrown.expect(NullPointerException.class);
+    new Option(null, VALUE) {};
+  }
+}
diff --git a/gcloud-java-translate/src/test/java/com/google/cloud/translate/TranslateImplTest.java b/gcloud-java-translate/src/test/java/com/google/cloud/translate/TranslateImplTest.java
new file mode 100644
index 000000000000..73bca24c118b
--- /dev/null
+++ b/gcloud-java-translate/src/test/java/com/google/cloud/translate/TranslateImplTest.java
@@ -0,0 +1,158 @@
+/*
+ * Copyright 2016 Google Inc. All Rights Reserved.
+ *
+ * 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
+ *
+ *       http://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 com.google.cloud.translate;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertSame;
+
+import com.google.api.services.translate.model.LanguagesResource;
+import com.google.cloud.RetryParams;
+import com.google.cloud.translate.Translate.LanguageListOption;
+import com.google.cloud.translate.spi.TranslateRpc;
+import com.google.cloud.translate.spi.TranslateRpcFactory;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+
+import org.easymock.EasyMock;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+import java.util.List;
+import java.util.Map;
+
+public class TranslateImplTest {
+
+  private static final String API_KEY = "api_key";
+  private static final String TARGET_LANGUAGE = "es";
+
+  private static final LanguagesResource LANGUAGE1_PB =
+      new LanguagesResource().setLanguage("en").setName("english");
+  private static final LanguagesResource LANGUAGE2_PB =
+      new LanguagesResource().setLanguage("es").setName("spanish");
+  private static final LanguagesResource LANGUAGE3_PB =
+      new LanguagesResource().setLanguage("en").setName("inglés");
+  private static final LanguagesResource LANGUAGE4_PB =
+      new LanguagesResource().setLanguage("es").setName("español");
+  private static final Language LANGUAGE1 = Language.fromPb(LANGUAGE1_PB);
+  private static final Language LANGUAGE2 = Language.fromPb(LANGUAGE2_PB);
+  private static final Language LANGUAGE3 = Language.fromPb(LANGUAGE3_PB);
+  private static final Language LANGUAGE4 = Language.fromPb(LANGUAGE4_PB);
+  private static final List<Language> LANGUAGES1 = ImmutableList.of(LANGUAGE1, LANGUAGE2);
+  private static final List<Language> LANGUAGES2 = ImmutableList.of(LANGUAGE3, LANGUAGE4);
+
+  // Empty TranslateRpc options
+  private static final Map<TranslateRpc.Option, ?> EMPTY_RPC_OPTIONS = ImmutableMap.of();
+
+  // Language list options
+  private static final LanguageListOption LANGUAGE_LIST_OPTION =
+      LanguageListOption.targetLanguage(TARGET_LANGUAGE);
+  private static final Map<TranslateRpc.Option, ?> LANGUAGE_LIST_OPTIONS = ImmutableMap.of(
+      TranslateRpc.Option.TARGET_LANGUAGE, LANGUAGE_LIST_OPTION.value());
+
+  private TranslateOptions options;
+  private TranslateRpcFactory rpcFactoryMock;
+  private TranslateRpc translateRpcMock;
+  private Translate translate;
+
+  @Rule
+  public ExpectedException thrown = ExpectedException.none();
+
+  @Before
+  public void setUp() {
+    rpcFactoryMock = EasyMock.createMock(TranslateRpcFactory.class);
+    translateRpcMock = EasyMock.createMock(TranslateRpc.class);
+    EasyMock.expect(rpcFactoryMock.create(EasyMock.anyObject(TranslateOptions.class)))
+        .andReturn(translateRpcMock);
+    EasyMock.replay(rpcFactoryMock);
+    options = TranslateOptions.builder(API_KEY)
+        .serviceRpcFactory(rpcFactoryMock)
+        .retryParams(RetryParams.noRetries())
+        .build();
+  }
+
+  @After
+  public void tearDown() throws Exception {
+    EasyMock.verify(rpcFactoryMock, translateRpcMock);
+  }
+
+  private void initializeService() {
+    translate = options.service();
+  }
+
+  @Test
+  public void testGetOptions() {
+    EasyMock.replay(translateRpcMock);
+    initializeService();
+    assertSame(options, translate.options());
+  }
+
+  @Test
+  public void testListSupporteLanguages() {
+    EasyMock.expect(translateRpcMock.listSupportedLanguages(EMPTY_RPC_OPTIONS))
+        .andReturn(ImmutableList.of(LANGUAGE1_PB, LANGUAGE2_PB));
+    EasyMock.replay(translateRpcMock);
+    initializeService();
+    assertEquals(LANGUAGES1, translate.listSupportedLanguages());
+  }
+
+  @Test
+  public void testListSupporteLanguagesWithOptions() {
+    EasyMock.expect(translateRpcMock.listSupportedLanguages(LANGUAGE_LIST_OPTIONS))
+        .andReturn(ImmutableList.of(LANGUAGE3_PB, LANGUAGE4_PB));
+    EasyMock.replay(translateRpcMock);
+    initializeService();
+    assertEquals(LANGUAGES2, translate.listSupportedLanguages(
+        LanguageListOption.targetLanguage(TARGET_LANGUAGE)));
+  }
+
+  @Test
+  public void testRetryableException() {
+    EasyMock.expect(translateRpcMock.listSupportedLanguages(EMPTY_RPC_OPTIONS))
+        .andThrow(new TranslateException(500, "internalError"))
+        .andReturn(ImmutableList.of(LANGUAGE1_PB, LANGUAGE2_PB));
+    EasyMock.replay(translateRpcMock);
+    translate = options.toBuilder().retryParams(RetryParams.defaultInstance()).build().service();
+    assertEquals(LANGUAGES1, translate.listSupportedLanguages());
+  }
+
+  @Test
+  public void testNonRetryableException() {
+    String exceptionMessage = "Not Implemented";
+    EasyMock.expect(translateRpcMock.listSupportedLanguages(EMPTY_RPC_OPTIONS))
+        .andThrow(new TranslateException(501, exceptionMessage));
+    EasyMock.replay(translateRpcMock);
+    translate = options.toBuilder().retryParams(RetryParams.defaultInstance()).build().service();
+    thrown.expect(TranslateException.class);
+    thrown.expectMessage(exceptionMessage);
+    translate.listSupportedLanguages();
+  }
+
+  @Test
+  public void testRuntimeException() {
+    String exceptionMessage = "Artificial runtime exception";
+    EasyMock.expect(translateRpcMock.listSupportedLanguages(EMPTY_RPC_OPTIONS))
+        .andThrow(new RuntimeException(exceptionMessage));
+    EasyMock.replay(translateRpcMock);
+    translate = options.toBuilder().retryParams(RetryParams.defaultInstance()).build().service();
+    thrown.expect(TranslateException.class);
+    thrown.expectMessage(exceptionMessage);
+    translate.listSupportedLanguages();
+  }
+}