diff --git a/native-app/App.tsx b/native-app/App.tsx
index 1ed6fe1..fdd26dc 100644
--- a/native-app/App.tsx
+++ b/native-app/App.tsx
@@ -4,6 +4,7 @@ import { ClerkProvider, SignedIn, SignedOut, useAuth } from "@clerk/clerk-expo";
 import { tokenCache } from "@clerk/clerk-expo/token-cache";
 import { ActivityIndicator, StyleSheet, Text, View } from "react-native";
 
+import { I18nProvider, useI18n } from "./src/i18n/I18nProvider";
 import { useAppTheme } from "./src/lib/theme";
 import { SignInScreen } from "./src/screens/SignInScreen";
 import { StreamerScreen } from "./src/screens/StreamerScreen";
@@ -35,13 +36,22 @@ function AuthReadyGate() {
 }
 
 export default function App() {
+  return (
+    <I18nProvider>
+      <AppContent />
+    </I18nProvider>
+  );
+}
+
+function AppContent() {
   const theme = useAppTheme();
+  const { t } = useI18n();
 
   if (!publishableKey) {
     return (
       <View style={[styles.loadingWrap, { backgroundColor: theme.background }]}>
         <Text style={[styles.errorText, { color: theme.destructive }]}>
-          Missing EXPO_PUBLIC_CLERK_PUBLISHABLE_KEY
+          {t("missingClerkKey")}
         </Text>
       </View>
     );
diff --git a/native-app/README.md b/native-app/README.md
index 6435feb..d130961 100644
--- a/native-app/README.md
+++ b/native-app/README.md
@@ -8,6 +8,7 @@ Simple React Native streamer app that:
 - Captures Android screen with `getDisplayMedia()`
 - Hosts a room on `/ws/signaling` and streams to connected viewers
 - Uses matching light/dark palette semantics from the Helium web app
+- Includes built-in i18n for English and Spanish based on device locale
 
 ## Auth implementation notes (from Clerk docs via Context7)
 
diff --git a/native-app/src/hooks/useHeliumStreamer.ts b/native-app/src/hooks/useHeliumStreamer.ts
index 9039fbb..8b77294 100644
--- a/native-app/src/hooks/useHeliumStreamer.ts
+++ b/native-app/src/hooks/useHeliumStreamer.ts
@@ -8,6 +8,7 @@ import {
 } from "react-native-webrtc";
 
 import { getSignalingUrl } from "../lib/signaling";
+import type { MessageKey } from "../i18n/messages";
 import type {
   IncomingSignalingMessage,
   NativeIceServer,
@@ -23,7 +24,8 @@ interface PeerConnectionHandlers {
 }
 
 interface UseHeliumStreamerResult {
-  status: string;
+  statusKey: MessageKey;
+  statusParams?: Record<string, string | number>;
   roomCode: string;
   streamUrl: string | null;
   viewerCount: number;
@@ -78,7 +80,10 @@ export function useHeliumStreamer(
   const heartbeatRef = useRef<ReturnType<typeof setInterval> | null>(null);
   const peersRef = useRef<Record<string, RTCPeerConnection>>({});
 
-  const [status, setStatus] = useState<string>("idle");
+  const [statusKey, setStatusKey] = useState<MessageKey>("statusIdle");
+  const [statusParams, setStatusParams] = useState<
+    Record<string, string | number> | undefined
+  >(undefined);
   const [roomCode, setRoomCode] = useState<string>("");
   const [streamUrl, setStreamUrl] = useState<string | null>(null);
   const [viewerCount, setViewerCount] = useState<number>(0);
@@ -126,7 +131,8 @@ export function useHeliumStreamer(
     setRoomCode("");
     setStreamUrl(null);
     setIsSharing(false);
-    setStatus("stopped");
+    setStatusKey("statusStopped");
+    setStatusParams(undefined);
   }, [closeAllPeers]);
 
   const handleViewerJoined = useCallback(
@@ -169,7 +175,8 @@ export function useHeliumStreamer(
       };
 
       peerWithHandlers.onconnectionstatechange = (): void => {
-        setStatus(`viewer ${viewerId}: ${peer.connectionState}`);
+        setStatusKey("statusPeerState");
+        setStatusParams({ state: peer.connectionState });
       };
 
       const offer = (await peer.createOffer()) as NativeSessionDescriptionInit;
@@ -191,12 +198,14 @@ export function useHeliumStreamer(
 
       if (message.event === "room-created") {
         setRoomCode(message.roomId);
-        setStatus(`room code: ${message.roomId}`);
+        setStatusKey("statusRoomCreated");
+        setStatusParams({ roomId: message.roomId });
         return;
       }
 
       if (message.event === "viewer-joined") {
-        setStatus(`viewer joined: ${message.viewerId}`);
+        setStatusKey("statusViewerJoined");
+        setStatusParams(undefined);
         await handleViewerJoined(message.viewerId);
         return;
       }
@@ -232,7 +241,8 @@ export function useHeliumStreamer(
       }
 
       if (message.event === "error") {
-        setStatus(`error: ${message.message}`);
+        setStatusKey("statusError");
+        setStatusParams({ message: message.message });
       }
     },
     [handleViewerJoined],
@@ -242,11 +252,13 @@ export function useHeliumStreamer(
     stopSharing();
 
     if (!iceServers.length) {
-      setStatus("no preset selected");
+      setStatusKey("statusNoPreset");
+      setStatusParams(undefined);
       return;
     }
 
-    setStatus("requesting screen capture");
+    setStatusKey("statusRequestingCapture");
+    setStatusParams(undefined);
     const stream = await (mediaDevices as unknown as {
       getDisplayMedia: (constraints?: {
         video?: boolean;
@@ -264,12 +276,14 @@ export function useHeliumStreamer(
     const audioTrackCount = stream.getAudioTracks().length;
 
     if (!videoTrackCount) {
-      setStatus("screen capture started without video track");
+      setStatusKey("statusNoVideoTrack");
+      setStatusParams(undefined);
       stopSharing();
       return;
     }
 
-    setStatus(`capturing ${videoTrackCount} video / ${audioTrackCount} audio tracks`);
+    setStatusKey("statusCapturing");
+    setStatusParams({ video: videoTrackCount, audio: audioTrackCount });
 
     stream.getTracks().forEach((track) => {
       const streamTrack = track as unknown as MediaStreamTrack & {
@@ -280,13 +294,15 @@ export function useHeliumStreamer(
       };
     });
 
-    setStatus("connecting signaling");
+    setStatusKey("statusConnectingSignaling");
+    setStatusParams(undefined);
 
     const ws = new WebSocket(getSignalingUrl());
     wsRef.current = ws;
 
     ws.onopen = (): void => {
-      setStatus("creating room");
+      setStatusKey("statusCreatingRoom");
+      setStatusParams(undefined);
       sendMessage({ event: "create-room" });
 
       heartbeatRef.current = setInterval(() => {
@@ -299,7 +315,8 @@ export function useHeliumStreamer(
     };
 
     ws.onerror = (): void => {
-      setStatus("websocket error");
+      setStatusKey("statusWebsocketError");
+      setStatusParams(undefined);
     };
 
     ws.onclose = (): void => {
@@ -308,7 +325,8 @@ export function useHeliumStreamer(
         heartbeatRef.current = null;
       }
       if (isSharing) {
-        setStatus("websocket closed");
+        setStatusKey("statusWebsocketClosed");
+        setStatusParams(undefined);
       }
     };
   }, [handleIncomingMessage, iceServers, isSharing, sendMessage, stopSharing]);
@@ -320,7 +338,8 @@ export function useHeliumStreamer(
   }, [stopSharing]);
 
   return {
-    status,
+    statusKey,
+    statusParams,
     roomCode,
     streamUrl,
     viewerCount,
diff --git a/native-app/src/i18n/I18nProvider.tsx b/native-app/src/i18n/I18nProvider.tsx
new file mode 100644
index 0000000..1d100e0
--- /dev/null
+++ b/native-app/src/i18n/I18nProvider.tsx
@@ -0,0 +1,54 @@
+import { createContext, useContext, useMemo } from "react";
+
+import { messages, type Locale, type MessageKey } from "./messages";
+
+interface I18nContextValue {
+  locale: Locale;
+  t: (key: MessageKey, params?: Record<string, string | number>) => string;
+}
+
+const I18nContext = createContext<I18nContextValue | null>(null);
+
+function resolveLocale(): Locale {
+  const locale = Intl.DateTimeFormat().resolvedOptions().locale.toLowerCase();
+  return locale.startsWith("es") ? "es" : "en";
+}
+
+function translate(
+  locale: Locale,
+  key: MessageKey,
+  params?: Record<string, string | number>,
+): string {
+  const template = messages[locale][key] ?? messages.en[key] ?? key;
+
+  if (!params) {
+    return template;
+  }
+
+  return Object.entries(params).reduce((result, [paramKey, value]) => {
+    return result.replaceAll(`{${paramKey}}`, String(value));
+  }, template);
+}
+
+export function I18nProvider({ children }: { children: React.ReactNode }) {
+  const locale = resolveLocale();
+
+  const value = useMemo<I18nContextValue>(() => {
+    return {
+      locale,
+      t: (key, params) => translate(locale, key, params),
+    };
+  }, [locale]);
+
+  return <I18nContext.Provider value={value}>{children}</I18nContext.Provider>;
+}
+
+export function useI18n(): I18nContextValue {
+  const context = useContext(I18nContext);
+
+  if (!context) {
+    throw new Error("useI18n must be used within I18nProvider");
+  }
+
+  return context;
+}
diff --git a/native-app/src/i18n/messages.ts b/native-app/src/i18n/messages.ts
new file mode 100644
index 0000000..6d61f15
--- /dev/null
+++ b/native-app/src/i18n/messages.ts
@@ -0,0 +1,138 @@
+export type Locale = "en" | "es";
+
+export type MessageKey =
+  | "missingClerkKey"
+  | "appTitle"
+  | "signInSubtitle"
+  | "email"
+  | "password"
+  | "signIn"
+  | "signingIn"
+  | "signedIn"
+  | "signInFailed"
+  | "needsExtraStep"
+  | "loadingPresets"
+  | "couldNotReadToken"
+  | "noPresetsFound"
+  | "loadedIceServers"
+  | "failedToLoadPresets"
+  | "failedToParsePreset"
+  | "streamerTitle"
+  | "streamerSubtitle"
+  | "preset"
+  | "session"
+  | "status"
+  | "viewers"
+  | "defaultLabel"
+  | "startShare"
+  | "stop"
+  | "signOut"
+  | "previewActive"
+  | "previewIdle"
+  | "statusIdle"
+  | "statusStopped"
+  | "statusNoPreset"
+  | "statusRequestingCapture"
+  | "statusNoVideoTrack"
+  | "statusCapturing"
+  | "statusConnectingSignaling"
+  | "statusCreatingRoom"
+  | "statusRoomCreated"
+  | "statusViewerJoined"
+  | "statusPeerState"
+  | "statusWebsocketError"
+  | "statusWebsocketClosed"
+  | "statusError";
+
+type MessageMap = Record<MessageKey, string>;
+
+export const messages: Record<Locale, MessageMap> = {
+  en: {
+    missingClerkKey: "Missing EXPO_PUBLIC_CLERK_PUBLISHABLE_KEY",
+    appTitle: "Helium Native",
+    signInSubtitle: "Sign in with Clerk",
+    email: "Email",
+    password: "Password",
+    signIn: "Sign in",
+    signingIn: "Signing in...",
+    signedIn: "Signed in",
+    signInFailed: "Sign-in failed",
+    needsExtraStep: "Needs extra step: {status}",
+    loadingPresets: "Loading presets",
+    couldNotReadToken: "Could not read auth token",
+    noPresetsFound: "No presets found",
+    loadedIceServers: "Loaded {count} ICE server entries",
+    failedToLoadPresets: "Failed to load presets: {message}",
+    failedToParsePreset: "Failed to parse ICE servers from preset",
+    streamerTitle: "Helium Streamer",
+    streamerSubtitle: "Share your Android screen to Helium viewers",
+    preset: "Preset",
+    session: "Session",
+    status: "Status",
+    viewers: "Viewers",
+    defaultLabel: "default",
+    startShare: "Start screen share",
+    stop: "Stop",
+    signOut: "Sign out",
+    previewActive: "Screen capture active. Preview disabled to reduce latency.",
+    previewIdle: "Start sharing to broadcast this phone screen",
+    statusIdle: "Idle",
+    statusStopped: "Stopped",
+    statusNoPreset: "No preset selected",
+    statusRequestingCapture: "Requesting screen capture",
+    statusNoVideoTrack: "Screen capture started without video track",
+    statusCapturing: "Capturing {video} video / {audio} audio tracks",
+    statusConnectingSignaling: "Connecting signaling",
+    statusCreatingRoom: "Creating room",
+    statusRoomCreated: "Room code: {roomId}",
+    statusViewerJoined: "Viewer joined",
+    statusPeerState: "Peer state: {state}",
+    statusWebsocketError: "WebSocket error",
+    statusWebsocketClosed: "WebSocket closed",
+    statusError: "Error: {message}",
+  },
+  es: {
+    missingClerkKey: "Falta EXPO_PUBLIC_CLERK_PUBLISHABLE_KEY",
+    appTitle: "Helium Nativo",
+    signInSubtitle: "Inicia sesion con Clerk",
+    email: "Correo",
+    password: "Contrasena",
+    signIn: "Iniciar sesion",
+    signingIn: "Iniciando sesion...",
+    signedIn: "Sesion iniciada",
+    signInFailed: "Error al iniciar sesion",
+    needsExtraStep: "Falta un paso adicional: {status}",
+    loadingPresets: "Cargando presets",
+    couldNotReadToken: "No se pudo leer el token",
+    noPresetsFound: "No se encontraron presets",
+    loadedIceServers: "Se cargaron {count} entradas ICE",
+    failedToLoadPresets: "Error al cargar presets: {message}",
+    failedToParsePreset: "Error al parsear ICE del preset",
+    streamerTitle: "Helium Emisor",
+    streamerSubtitle: "Comparte la pantalla de Android con Helium",
+    preset: "Preset",
+    session: "Sesion",
+    status: "Estado",
+    viewers: "Espectadores",
+    defaultLabel: "predeterminado",
+    startShare: "Iniciar pantalla",
+    stop: "Detener",
+    signOut: "Cerrar sesion",
+    previewActive: "Captura activa. Vista previa desactivada para menor latencia.",
+    previewIdle: "Inicia la captura para transmitir esta pantalla",
+    statusIdle: "En espera",
+    statusStopped: "Detenido",
+    statusNoPreset: "No hay preset seleccionado",
+    statusRequestingCapture: "Solicitando captura de pantalla",
+    statusNoVideoTrack: "La captura inicio sin pista de video",
+    statusCapturing: "Capturando {video} video / {audio} audio",
+    statusConnectingSignaling: "Conectando senalizacion",
+    statusCreatingRoom: "Creando sala",
+    statusRoomCreated: "Codigo de sala: {roomId}",
+    statusViewerJoined: "Se unio un espectador",
+    statusPeerState: "Estado del peer: {state}",
+    statusWebsocketError: "Error de WebSocket",
+    statusWebsocketClosed: "WebSocket cerrado",
+    statusError: "Error: {message}",
+  },
+};
diff --git a/native-app/src/screens/SignInScreen.tsx b/native-app/src/screens/SignInScreen.tsx
index 5badce3..861a9f1 100644
--- a/native-app/src/screens/SignInScreen.tsx
+++ b/native-app/src/screens/SignInScreen.tsx
@@ -10,9 +10,11 @@ import {
 } from "react-native";
 
 import { useAppTheme } from "../lib/theme";
+import { useI18n } from "../i18n/I18nProvider";
 
 export function SignInScreen() {
   const theme = useAppTheme();
+  const { t } = useI18n();
   const { isLoaded, signIn, setActive } = useSignIn();
   const [email, setEmail] = useState<string>("");
   const [password, setPassword] = useState<string>("");
@@ -24,7 +26,7 @@ export function SignInScreen() {
       return;
     }
 
-    setStatus("Signing in...");
+    setStatus(t("signingIn"));
 
     try {
       const attempt = await signIn.create({
@@ -34,33 +36,33 @@ export function SignInScreen() {
 
       if (attempt.status === "complete") {
         await setActive({ session: attempt.createdSessionId });
-        setStatus("Signed in");
+        setStatus(t("signedIn"));
         return;
       }
 
-      setStatus(`Needs extra step: ${attempt.status}`);
+      setStatus(t("needsExtraStep", { status: String(attempt.status) }));
     } catch {
-      setStatus("Sign-in failed");
+      setStatus(t("signInFailed"));
     }
   };
 
   return (
     <View style={styles.container}>
-      <Text style={styles.title}>Helium Native</Text>
-      <Text style={styles.subtitle}>Sign in with Clerk</Text>
+      <Text style={styles.title}>{t("appTitle")}</Text>
+      <Text style={styles.subtitle}>{t("signInSubtitle")}</Text>
 
       <TextInput
         autoCapitalize="none"
         keyboardType="email-address"
         onChangeText={setEmail}
-        placeholder="Email"
+        placeholder={t("email")}
         placeholderTextColor="#7e8794"
         style={styles.input}
         value={email}
       />
       <TextInput
         onChangeText={setPassword}
-        placeholder="Password"
+        placeholder={t("password")}
         placeholderTextColor="#7e8794"
         secureTextEntry
         style={styles.input}
@@ -75,7 +77,7 @@ export function SignInScreen() {
         style={styles.button}
       >
         {isLoaded ? (
-          <Text style={styles.buttonText}>Sign in</Text>
+          <Text style={styles.buttonText}>{t("signIn")}</Text>
         ) : (
           <ActivityIndicator color={theme.primaryForeground} />
         )}
diff --git a/native-app/src/screens/StreamerScreen.tsx b/native-app/src/screens/StreamerScreen.tsx
index c408323..dd65ce7 100644
--- a/native-app/src/screens/StreamerScreen.tsx
+++ b/native-app/src/screens/StreamerScreen.tsx
@@ -10,6 +10,8 @@ import {
 } from "react-native";
 
 import { useHeliumStreamer } from "../hooks/useHeliumStreamer";
+import { useI18n } from "../i18n/I18nProvider";
+import type { MessageKey } from "../i18n/messages";
 import { useAppTheme } from "../lib/theme";
 import { getPresets } from "../lib/presets";
 import type { NativeIceServer, PresetUser } from "../types/presets";
@@ -17,16 +19,21 @@ import type { NativeIceServer, PresetUser } from "../types/presets";
 export function StreamerScreen() {
   const { getToken, signOut } = useAuth();
   const theme = useAppTheme();
+  const { t } = useI18n();
 
   const [presets, setPresets] = useState<PresetUser[]>([]);
   const [presetId, setPresetId] = useState<string>("");
   const [iceServers, setIceServers] = useState<NativeIceServer[]>([]);
-  const [presetStatus, setPresetStatus] = useState<string>("loading presets");
+  const [presetStatusKey, setPresetStatusKey] = useState<MessageKey>("loadingPresets");
+  const [presetStatusParams, setPresetStatusParams] = useState<
+    Record<string, string | number> | undefined
+  >(undefined);
 
   const styles = useMemo(() => createStyles(theme), [theme]);
 
   const {
-    status,
+    statusKey,
+    statusParams,
     roomCode,
     viewerCount,
     isSharing,
@@ -43,7 +50,8 @@ export function StreamerScreen() {
       const token = await getToken();
 
       if (!token) {
-        setPresetStatus("could not read auth token");
+        setPresetStatusKey("couldNotReadToken");
+        setPresetStatusParams(undefined);
         return;
       }
 
@@ -52,7 +60,8 @@ export function StreamerScreen() {
         setPresets(availablePresets);
 
         if (!availablePresets.length) {
-          setPresetStatus("no presets found");
+          setPresetStatusKey("noPresetsFound");
+          setPresetStatusParams(undefined);
           return;
         }
 
@@ -61,7 +70,8 @@ export function StreamerScreen() {
 
         setPresetId(defaultPreset.presetId);
       } catch (error) {
-        setPresetStatus(`failed to load presets: ${(error as Error).message}`);
+        setPresetStatusKey("failedToLoadPresets");
+        setPresetStatusParams({ message: (error as Error).message });
       }
     };
 
@@ -82,22 +92,24 @@ export function StreamerScreen() {
           : rawIceServers;
 
       setIceServers(parsedIceServers ?? []);
-      setPresetStatus(`loaded ${(parsedIceServers ?? []).length} ICE server entries`);
+      setPresetStatusKey("loadedIceServers");
+      setPresetStatusParams({ count: (parsedIceServers ?? []).length });
     } catch {
       setIceServers([]);
-      setPresetStatus("failed to parse ICE servers from preset");
+      setPresetStatusKey("failedToParsePreset");
+      setPresetStatusParams(undefined);
     }
   }, [selectedPreset]);
 
   return (
     <SafeAreaView style={styles.safeArea}>
       <ScrollView contentContainerStyle={styles.container}>
-        <Text style={styles.title}>Helium Streamer</Text>
-        <Text style={styles.subtitle}>Share your Android screen to Helium viewers</Text>
+        <Text style={styles.title}>{t("streamerTitle")}</Text>
+        <Text style={styles.subtitle}>{t("streamerSubtitle")}</Text>
 
         <View style={styles.card}>
-          <Text style={styles.cardTitle}>Preset</Text>
-          <Text style={styles.small}>{presetStatus}</Text>
+          <Text style={styles.cardTitle}>{t("preset")}</Text>
+          <Text style={styles.small}>{t(presetStatusKey, presetStatusParams)}</Text>
 
           <View style={styles.presetList}>
             {presets.map((preset) => {
@@ -117,7 +129,7 @@ export function StreamerScreen() {
                     ]}
                   >
                     {preset.preset.name}
-                    {preset.isDefault ? " (default)" : ""}
+                    {preset.isDefault ? ` (${t("defaultLabel")})` : ""}
                   </Text>
                 </Pressable>
               );
@@ -126,9 +138,9 @@ export function StreamerScreen() {
         </View>
 
         <View style={styles.card}>
-          <Text style={styles.cardTitle}>Session</Text>
-          <Text style={styles.small}>Status: {status}</Text>
-          <Text style={styles.small}>Viewers: {viewerCount}</Text>
+          <Text style={styles.cardTitle}>{t("session")}</Text>
+          <Text style={styles.small}>{t("status")}: {t(statusKey, statusParams)}</Text>
+          <Text style={styles.small}>{t("viewers")}: {viewerCount}</Text>
           <Text style={styles.roomCode}>{roomCode || "------"}</Text>
 
           <View style={styles.actions}>
@@ -138,11 +150,11 @@ export function StreamerScreen() {
               }}
               style={styles.primaryButton}
             >
-              <Text style={styles.primaryButtonText}>Start screen share</Text>
+              <Text style={styles.primaryButtonText}>{t("startShare")}</Text>
             </Pressable>
 
             <Pressable onPress={stopSharing} style={styles.secondaryButton}>
-              <Text style={styles.secondaryButtonText}>Stop</Text>
+              <Text style={styles.secondaryButtonText}>{t("stop")}</Text>
             </Pressable>
           </View>
         </View>
@@ -150,10 +162,10 @@ export function StreamerScreen() {
         <View style={styles.preview}>
           {isSharing ? (
             <Text style={styles.previewPlaceholder}>
-              Screen capture active. Preview disabled to reduce latency.
+              {t("previewActive")}
             </Text>
           ) : (
-            <Text style={styles.previewPlaceholder}>Start sharing to broadcast this phone screen</Text>
+            <Text style={styles.previewPlaceholder}>{t("previewIdle")}</Text>
           )}
         </View>
 
@@ -163,7 +175,7 @@ export function StreamerScreen() {
           }}
           style={styles.signOutButton}
         >
-          <Text style={styles.signOutText}>Sign out</Text>
+          <Text style={styles.signOutText}>{t("signOut")}</Text>
         </Pressable>
       </ScrollView>
     </SafeAreaView>