diff --git a/app/src/main/java/com/x8bit/bitwarden/ui/tools/feature/generator/GeneratorScreen.kt b/app/src/main/java/com/x8bit/bitwarden/ui/tools/feature/generator/GeneratorScreen.kt
index 8d684c839..72089a168 100644
--- a/app/src/main/java/com/x8bit/bitwarden/ui/tools/feature/generator/GeneratorScreen.kt
+++ b/app/src/main/java/com/x8bit/bitwarden/ui/tools/feature/generator/GeneratorScreen.kt
@@ -868,7 +868,14 @@ private fun ColumnScope.ForwardedEmailAliasTypeContent(
         }
 
         is ServiceType.FastMail -> {
-            // TODO: FastMail Service Implementation (BIT-712)
+            BitwardenPasswordField(
+                label = stringResource(id = R.string.api_key_required_parenthesis),
+                value = usernameTypeState.selectedServiceType.apiKey,
+                onValueChange = forwardedEmailAliasHandlers.onFastMailApiKeyTextChange,
+                modifier = Modifier
+                    .padding(horizontal = 16.dp)
+                    .fillMaxWidth(),
+            )
         }
 
         is ServiceType.FirefoxRelay -> {
@@ -1207,6 +1214,7 @@ private class ForwardedEmailAliasHandlers(
     val onAddyIoAccessTokenTextChange: (String) -> Unit,
     val onAddyIoDomainNameTextChange: (String) -> Unit,
     val onDuckDuckGoApiKeyTextChange: (String) -> Unit,
+    val onFastMailApiKeyTextChange: (String) -> Unit,
     val onFirefoxRelayAccessTokenTextChange: (String) -> Unit,
 ) {
     companion object {
@@ -1264,6 +1272,19 @@ private class ForwardedEmailAliasHandlers(
                             ),
                     )
                 },
+                onFastMailApiKeyTextChange = { newApiKey ->
+                    viewModel.trySendAction(
+                        GeneratorAction
+                            .MainType
+                            .Username
+                            .UsernameType
+                            .ForwardedEmailAlias
+                            .FastMail
+                            .ApiKeyTextChange(
+                                apiKey = newApiKey,
+                            ),
+                    )
+                },
                 onFirefoxRelayAccessTokenTextChange = { newAccessToken ->
                     viewModel.trySendAction(
                         GeneratorAction
diff --git a/app/src/main/java/com/x8bit/bitwarden/ui/tools/feature/generator/GeneratorViewModel.kt b/app/src/main/java/com/x8bit/bitwarden/ui/tools/feature/generator/GeneratorViewModel.kt
index 5f78fd407..c74399dda 100644
--- a/app/src/main/java/com/x8bit/bitwarden/ui/tools/feature/generator/GeneratorViewModel.kt
+++ b/app/src/main/java/com/x8bit/bitwarden/ui/tools/feature/generator/GeneratorViewModel.kt
@@ -126,6 +126,10 @@ class GeneratorViewModel @Inject constructor(
                 handleDuckDuckGoTextInputChange(action)
             }
 
+            is GeneratorAction.MainType.Username.UsernameType.ForwardedEmailAlias.FastMail.ApiKeyTextChange -> {
+                handleFastMailTextInputChange(action)
+            }
+
             is GeneratorAction.MainType.Username.UsernameType.ForwardedEmailAlias.FirefoxRelay.AccessTokenTextChange -> {
                 handleFirefoxRelayTextInputChange(action)
             }
@@ -692,6 +696,25 @@ class GeneratorViewModel @Inject constructor(
 
     //endregion DuckDuckGo Service Specific Handlers
 
+    //region FastMail Service Specific Handlers
+
+    private fun handleFastMailTextInputChange(
+        action: GeneratorAction
+        .MainType
+        .Username
+        .UsernameType
+        .ForwardedEmailAlias
+        .FastMail
+        .ApiKeyTextChange,
+    ) {
+        updateFastMailServiceType { fastMailServiceType ->
+            val newApiKey = action.apiKey
+            fastMailServiceType.copy(apiKey = newApiKey)
+        }
+    }
+
+    //endregion FastMail Service Specific Handlers
+
     //region FirefoxRelay Service Specific Handlers
 
     private fun handleFirefoxRelayTextInputChange(
@@ -917,6 +940,30 @@ class GeneratorViewModel @Inject constructor(
         }
     }
 
+    private inline fun updateFastMailServiceType(
+        crossinline block: (FastMail) -> FastMail,
+    ) {
+        updateGeneratorMainTypeUsername { currentUsernameType ->
+            if (currentUsernameType.selectedType !is ForwardedEmailAlias) {
+                return@updateGeneratorMainTypeUsername currentUsernameType
+            }
+
+            val currentServiceType = (currentUsernameType.selectedType).selectedServiceType
+            if (currentServiceType !is FastMail) {
+                return@updateGeneratorMainTypeUsername currentUsernameType
+            }
+
+            val updatedServiceType = block(currentServiceType)
+
+            currentUsernameType.copy(
+                selectedType = ForwardedEmailAlias(
+                    selectedServiceType = updatedServiceType,
+                    obfuscatedText = currentUsernameType.selectedType.obfuscatedText,
+                ),
+            )
+        }
+    }
+
     private inline fun updateFirefoxRelayServiceType(
         crossinline block: (FirefoxRelay) -> FirefoxRelay,
     ) {
@@ -1624,6 +1671,19 @@ sealed class GeneratorAction {
                         data class ApiKeyTextChange(val apiKey: String) : DuckDuckGo()
                     }
 
+                    /**
+                     * Represents actions specifically related to the FastMail service.
+                     */
+                    sealed class FastMail : ForwardedEmailAlias() {
+
+                        /**
+                         * Fired when the api key input text is changed.
+                         *
+                         * @property apiKey The new api key text.
+                         */
+                        data class ApiKeyTextChange(val apiKey: String) : FastMail()
+                    }
+
                     /**
                      * Represents actions specifically related to the FirefoxRelay service.
                      */
diff --git a/app/src/test/java/com/x8bit/bitwarden/ui/tools/feature/generator/GeneratorScreenTest.kt b/app/src/test/java/com/x8bit/bitwarden/ui/tools/feature/generator/GeneratorScreenTest.kt
index a5edecf9a..24bdbaee1 100644
--- a/app/src/test/java/com/x8bit/bitwarden/ui/tools/feature/generator/GeneratorScreenTest.kt
+++ b/app/src/test/java/com/x8bit/bitwarden/ui/tools/feature/generator/GeneratorScreenTest.kt
@@ -1055,6 +1055,46 @@ class GeneratorScreenTest : BaseComposeTest() {
 
     //endregion DuckDuckGo Service Type Tests
 
+    //region FastMail Service Type Tests
+
+    @Suppress("MaxLineLength")
+    @Test
+    fun `in Username_ForwardedEmailAlias_FastMail state, updating api key text input should send ApiKeyTextChange action`() {
+        updateState(
+            GeneratorState(
+                generatedText = "Placeholder",
+                selectedType = GeneratorState.MainType.Username(
+                    GeneratorState.MainType.Username.UsernameType.ForwardedEmailAlias(
+                        selectedServiceType = GeneratorState
+                            .MainType
+                            .Username
+                            .UsernameType
+                            .ForwardedEmailAlias
+                            .ServiceType
+                            .FastMail(),
+                    ),
+                ),
+            ),
+        )
+
+        val newApiKey = "apiKey"
+
+        composeTestRule
+            .onNodeWithText("API key (required)")
+            .performScrollTo()
+            .performTextInput(newApiKey)
+
+        verify {
+            viewModel.trySendAction(
+                GeneratorAction.MainType.Username.UsernameType.ForwardedEmailAlias.FastMail.ApiKeyTextChange(
+                    apiKey = newApiKey,
+                ),
+            )
+        }
+    }
+
+    //endregion FastMail Service Type Tests
+
     //region FirefoxRelay Service Type Tests
 
     @Suppress("MaxLineLength")
diff --git a/app/src/test/java/com/x8bit/bitwarden/ui/tools/feature/generator/GeneratorViewModelTest.kt b/app/src/test/java/com/x8bit/bitwarden/ui/tools/feature/generator/GeneratorViewModelTest.kt
index 4f248b95d..17020e03a 100644
--- a/app/src/test/java/com/x8bit/bitwarden/ui/tools/feature/generator/GeneratorViewModelTest.kt
+++ b/app/src/test/java/com/x8bit/bitwarden/ui/tools/feature/generator/GeneratorViewModelTest.kt
@@ -37,6 +37,9 @@ class GeneratorViewModelTest : BaseViewModelTest() {
     private val initialDuckDuckGoState = createDuckDuckGoState()
     private val duckDuckGoSavedStateHandle = createSavedStateHandleWithState(initialDuckDuckGoState)
 
+    private val initialFastMailState = createFastMailState()
+    private val fastMailSavedStateHandle = createSavedStateHandleWithState(initialFastMailState)
+
     private val initialFirefoxRelay = createFirefoxRelayState()
     private val firefoxRelaySavedStateHandle = createSavedStateHandleWithState(initialFirefoxRelay)
 
@@ -1083,6 +1086,50 @@ class GeneratorViewModelTest : BaseViewModelTest() {
         }
     }
 
+    @Nested
+    inner class FastMailActions {
+        private val defaultFastMailState = createFastMailState()
+        private lateinit var viewModel: GeneratorViewModel
+
+        @BeforeEach
+        fun setup() {
+            viewModel = GeneratorViewModel(fastMailSavedStateHandle, fakeGeneratorRepository)
+        }
+
+        @Test
+        fun `ApiKeyTextChange should update api key text correctly`() = runTest {
+            val newApiKey = "newApiKey"
+            val action = GeneratorAction
+                .MainType
+                .Username
+                .UsernameType
+                .ForwardedEmailAlias
+                .FastMail.ApiKeyTextChange(
+                    apiKey = newApiKey,
+                )
+
+            viewModel.actionChannel.trySend(action)
+
+            val expectedState = defaultFastMailState.copy(
+                selectedType = GeneratorState.MainType.Username(
+                    GeneratorState.MainType.Username.UsernameType.ForwardedEmailAlias(
+                        selectedServiceType = GeneratorState
+                            .MainType
+                            .Username
+                            .UsernameType
+                            .ForwardedEmailAlias
+                            .ServiceType
+                            .FastMail(
+                                apiKey = newApiKey,
+                            ),
+                    ),
+                ),
+            )
+
+            assertEquals(expectedState, viewModel.stateFlow.value)
+        }
+    }
+
     @Nested
     inner class FirefoxRelayActions {
         private val defaultFirefoxRelayState = createFirefoxRelayState()
@@ -1371,6 +1418,24 @@ class GeneratorViewModelTest : BaseViewModelTest() {
             ),
         )
 
+    private fun createFastMailState(
+        generatedText: String = "defaultFastMail",
+    ): GeneratorState =
+        GeneratorState(
+            generatedText = generatedText,
+            selectedType = GeneratorState.MainType.Username(
+                GeneratorState.MainType.Username.UsernameType.ForwardedEmailAlias(
+                    selectedServiceType = GeneratorState
+                        .MainType
+                        .Username
+                        .UsernameType
+                        .ForwardedEmailAlias
+                        .ServiceType
+                        .FastMail(),
+                ),
+            ),
+        )
+
     private fun createFirefoxRelayState(
         generatedText: String = "defaultFirefoxRelay",
     ): GeneratorState =