diff --git a/src/__tests__/SubmitProofScreen.test.tsx b/src/__tests__/SubmitProofScreen.test.tsx
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+++ b/src/__tests__/SubmitProofScreen.test.tsx
@@ -0,0 +1,454 @@
+/**
+ * SubmitProofScreen.test.tsx
+ *
+ * Covers the core proof submission flow:
+ *  - camera permission, device availability and photo capture
+ *  - successful submission (activity + stats + polling + notification)
+ *  - offline / queued submission with error display
+ *  - retake photo reset
+ *  - empty state when no task id is present
+ *  - location display and location errors
+ *  - progress labels and submitting states
+ */
+
+// react-native-vision-camera must be mocked before the screen is imported.
+const mockCameraTakePhoto = jest.fn();
+const mockUseCameraPermission = jest.fn();
+const mockUseCameraDevice = jest.fn();
+const mockRequestPermission = jest.fn();
+
+jest.mock('react-native-vision-camera', () => {
+  const React = require('react');
+  return {
+    useCameraPermission: (...args: unknown[]) =>
+      mockUseCameraPermission(...args),
+    useCameraDevice: (...args: unknown[]) => mockUseCameraDevice(...args),
+    Camera: React.forwardRef((props: any, ref: any) => {
+      void props;
+      React.useImperativeHandle(ref, () => ({
+        takePhoto: mockCameraTakePhoto,
+      }));
+      return null;
+    }),
+  };
+});
+
+const mockRoute: { params: any } = {
+  params: {
+    taskId: 't1',
+    taskTitle: 'Plant a tree',
+    taskType: 'TREE_PLANTING',
+    rewardAmount: 25,
+    rewardToken: 'ECO',
+  },
+};
+const mockGoBack = jest.fn();
+
+jest.mock('@react-navigation/native', () => ({
+  useRoute: jest.fn(() => mockRoute),
+  useNavigation: jest.fn(() => ({ goBack: mockGoBack })),
+}));
+
+const mockLocation: {
+  location: { lat: number; lng: number } | null;
+  permissionGranted: boolean;
+  error: string | null;
+  refresh: jest.Mock;
+} = {
+  location: { lat: 1.2345, lng: 6.789 },
+  permissionGranted: true,
+  error: null,
+  refresh: jest.fn(),
+};
+
+jest.mock('../hooks/useLocation', () => ({
+  useLocation: jest.fn(() => mockLocation),
+}));
+
+const mockProofSubmitHook: {
+  submit: jest.Mock;
+  syncPendingProofs: jest.Mock;
+  pendingCount: number;
+  isSubmitting: boolean;
+  progress: string;
+  error: string | null;
+} = {
+  submit: jest.fn(),
+  syncPendingProofs: jest.fn(),
+  pendingCount: 0,
+  isSubmitting: false,
+  progress: 'idle',
+  error: null,
+};
+
+jest.mock('../hooks/useProofSubmit', () => ({
+  useProofSubmit: jest.fn(() => mockProofSubmitHook),
+}));
+
+const mockUseProofStatus = jest.fn();
+
+jest.mock('../hooks/useProofStatus', () => ({
+  useProofStatus: (...args: unknown[]) => mockUseProofStatus(...args),
+}));
+
+jest.mock('../services/notifications', () => ({
+  scheduleLocalNotification: jest.fn(),
+  NOTIFICATION_TYPES: {
+    REWARD_CONFIRMED: 'reward_confirmed',
+  },
+}));
+
+import './__mocks__/setup';
+
+import React from 'react';
+import renderer, { act } from 'react-test-renderer';
+import { Alert, Image, Text, TouchableOpacity } from 'react-native';
+import SubmitProofScreen from '../screens/SubmitProofScreen';
+import { useActivityStore } from '../store/activityStore';
+import { useUserStore } from '../store/userStore';
+import { scheduleLocalNotification } from '../services/notifications';
+
+const BASE_PARAMS = {
+  taskId: 't1',
+  taskTitle: 'Plant a tree',
+  taskType: 'TREE_PLANTING',
+  rewardAmount: 25,
+  rewardToken: 'ECO',
+};
+
+function textValues(tree: renderer.ReactTestRenderer): string[] {
+  return tree.root
+    .findAllByType(Text)
+    .flatMap(node =>
+      (Array.isArray(node.props.children)
+        ? node.props.children
+        : [node.props.children]
+      ).filter((child: unknown): child is string => typeof child === 'string'),
+    );
+}
+
+function buttonByLabel(tree: renderer.ReactTestRenderer, label: string) {
+  return tree.root.findAllByType(TouchableOpacity).find(btn =>
+    btn.findAllByType(Text).some(t => {
+      const children = Array.isArray(t.props.children)
+        ? t.props.children
+        : [t.props.children];
+      return children.includes(label);
+    }),
+  );
+}
+
+function renderScreen(): renderer.ReactTestRenderer {
+  let tree!: renderer.ReactTestRenderer;
+  act(() => {
+    tree = renderer.create(<SubmitProofScreen />);
+  });
+  return tree;
+}
+
+async function pressButton(tree: renderer.ReactTestRenderer, label: string) {
+  const btn = buttonByLabel(tree, label);
+  expect(btn).toBeDefined();
+  await act(async () => {
+    await btn!.props.onPress();
+  });
+}
+
+beforeEach(() => {
+  jest.restoreAllMocks();
+  jest.clearAllMocks();
+  mockRoute.params = { ...BASE_PARAMS };
+  mockCameraTakePhoto.mockReset().mockResolvedValue({ path: 'photo.jpg' });
+  mockUseCameraPermission.mockReturnValue({
+    hasPermission: true,
+    requestPermission: mockRequestPermission,
+  });
+  mockUseCameraDevice.mockReturnValue({ id: 'back' });
+  mockLocation.location = { lat: 1.2345, lng: 6.789 };
+  mockLocation.error = null;
+  mockProofSubmitHook.submit = jest.fn();
+  mockProofSubmitHook.isSubmitting = false;
+  mockProofSubmitHook.progress = 'idle';
+  mockProofSubmitHook.error = null;
+  useActivityStore.setState({ activities: [], streak: 0, bestStreak: 0 });
+  useUserStore.setState({
+    profile: {
+      id: 'u1',
+      wallet: 'GDQXXXX',
+      stats: { treesPlanted: 0, plasticCollected: 0, co2Reduced: 0 },
+    },
+    token: null,
+    tokenExpiresAt: null,
+  });
+});
+
+describe('SubmitProofScreen', () => {
+  let tree: renderer.ReactTestRenderer | null = null;
+
+  afterEach(() => {
+    act(() => {
+      tree?.unmount();
+    });
+    tree = null;
+  });
+
+  it('shows an empty state when no task id is provided', () => {
+    mockRoute.params = { taskId: undefined };
+    tree = renderScreen();
+
+    const texts = textValues(tree);
+    expect(texts).toContain('Select a task first');
+    expect(texts).toContain('Browse available tasks');
+    expect(buttonByLabel(tree, 'Take Photo')).toBeUndefined();
+  });
+
+  it('renders the submit UI with the camera and location when available', () => {
+    tree = renderScreen();
+
+    expect(textValues(tree)).toContain('Submit Proof');
+    expect(buttonByLabel(tree, 'Take Photo')).toBeDefined();
+    expect(textValues(tree)).toContain('1.2345, 6.7890');
+  });
+
+  it('prompts for camera permission and requests it again on tap', async () => {
+    mockUseCameraPermission.mockReturnValue({
+      hasPermission: false,
+      requestPermission: mockRequestPermission,
+    });
+    tree = renderScreen();
+
+    expect(textValues(tree)).toContain('Camera permission required');
+    expect(buttonByLabel(tree, 'Grant Permission')).toBeDefined();
+    expect(mockRequestPermission).toHaveBeenCalled();
+
+    await pressButton(tree, 'Grant Permission');
+    expect(mockRequestPermission).toHaveBeenCalledTimes(2);
+  });
+
+  it('shows a no-camera message when no back camera device exists', () => {
+    mockUseCameraDevice.mockReturnValue(undefined);
+    tree = renderScreen();
+
+    expect(textValues(tree)).toContain('No camera available');
+    expect(buttonByLabel(tree, 'Take Photo')).toBeDefined();
+  });
+
+  it('captures a photo and shows the preview with retake and submit actions', async () => {
+    tree = renderScreen();
+    await pressButton(tree, 'Take Photo');
+
+    expect(mockCameraTakePhoto).toHaveBeenCalledWith({ flash: 'off' });
+    const preview = tree.root.findAllByType(Image);
+    expect(preview.length).toBeGreaterThan(0);
+    expect(preview[0]!.props.source).toEqual({ uri: 'file://photo.jpg' });
+    expect(buttonByLabel(tree, 'Retake')).toBeDefined();
+    expect(buttonByLabel(tree, 'Submit Proof')).toBeDefined();
+  });
+
+  it('alerts the user when capture fails and stays on capture mode', async () => {
+    const alertSpy = jest.spyOn(Alert, 'alert').mockImplementation(() => {});
+    mockCameraTakePhoto.mockRejectedValueOnce(new Error('camera broken'));
+    tree = renderScreen();
+    await pressButton(tree, 'Take Photo');
+
+    expect(alertSpy).toHaveBeenCalledWith('Camera Error', 'camera broken');
+    expect(tree.root.findAllByType(Image)).toHaveLength(0);
+    expect(buttonByLabel(tree, 'Take Photo')).toBeDefined();
+  });
+
+  it('disables the take-photo button while submitting', () => {
+    mockProofSubmitHook.isSubmitting = true;
+    tree = renderScreen();
+
+    const captureBtn = buttonByLabel(tree, '...');
+    expect(captureBtn).toBeDefined();
+    expect(captureBtn!.props.disabled).toBe(true);
+  });
+
+  it('shows a disabled submitting button while a captured proof uploads', async () => {
+    tree = renderScreen();
+    await pressButton(tree, 'Take Photo');
+
+    mockProofSubmitHook.isSubmitting = true;
+    act(() => {
+      tree!.update(<SubmitProofScreen />);
+    });
+
+    const submitBtn = buttonByLabel(tree, 'Submitting...');
+    expect(submitBtn).toBeDefined();
+    expect(submitBtn!.props.disabled).toBe(true);
+  });
+
+  it('successful submission adds a pending activity, updates stats, starts polling, and defers the notification', async () => {
+    tree = renderScreen();
+    await pressButton(tree, 'Take Photo');
+
+    mockProofSubmitHook.progress = 'verifying';
+    mockProofSubmitHook.submit.mockResolvedValue({
+      proofId: 'proof-1',
+      taskTitle: 'Plant a tree',
+      taskType: 'TREE_PLANTING',
+      rewardAmount: 25,
+      rewardToken: 'ECO',
+    });
+
+    await pressButton(tree, 'Submit Proof');
+
+    expect(mockProofSubmitHook.submit).toHaveBeenCalledWith(
+      't1',
+      'file://photo.jpg',
+      expect.any(String),
+      1.2345,
+      6.789,
+    );
+
+    const activities = useActivityStore.getState().activities;
+    expect(activities).toHaveLength(1);
+    const activity = activities[0]!;
+    expect(activity).toEqual(
+      expect.objectContaining({
+        taskId: 't1',
+        taskTitle: 'Plant a tree',
+        taskType: 'TREE_PLANTING',
+        rewardAmount: 25,
+        rewardToken: 'ECO',
+        status: 'pending',
+        proofId: 'proof-1',
+      }),
+    );
+
+    const stats = useUserStore.getState().profile?.stats;
+    expect(stats?.treesPlanted).toBe(1);
+    expect(stats?.co2Reduced).toBe(2);
+
+    expect(mockUseProofStatus).toHaveBeenCalledWith(
+      'proof-1',
+      expect.objectContaining({
+        activityId: activity.id,
+        taskTitle: 'Plant a tree',
+        rewardToken: 'ECO',
+      }),
+    );
+
+    expect(scheduleLocalNotification).not.toHaveBeenCalled();
+    expect(textValues(tree)).toContain('Verifying proof — reward pending...');
+  });
+
+  it('successful submission without a proofId confirms the activity and fires a reward notification', async () => {
+    tree = renderScreen();
+    await pressButton(tree, 'Take Photo');
+
+    mockProofSubmitHook.progress = 'verifying';
+    mockProofSubmitHook.submit.mockResolvedValue({ success: true });
+
+    await pressButton(tree, 'Submit Proof');
+
+    const activity = useActivityStore.getState().activities[0]!;
+    expect(activity.status).toBe('confirmed');
+    expect(activity.rewardAmount).toBe(25);
+
+    const stats = useUserStore.getState().profile?.stats;
+    expect(stats?.treesPlanted).toBe(1);
+
+    expect(scheduleLocalNotification).toHaveBeenCalledWith(
+      expect.objectContaining({
+        title: 'Reward confirmed! 🎉',
+        body: 'You earned 25 ECO for "Plant a tree".',
+        type: 'reward_confirmed',
+        data: expect.objectContaining({
+          activityId: activity.id,
+          deepLink: 'ecotask://wallet',
+        }),
+      }),
+    );
+
+    expect(textValues(tree)).toContain('Verifying with network...');
+  });
+
+  it('offline submission queues a pending activity and shows the error', async () => {
+    mockRoute.params = { taskId: 't1', taskType: 'OTHER', rewardToken: 'ECO' };
+    tree = renderScreen();
+    await pressButton(tree, 'Take Photo');
+
+    mockProofSubmitHook.error = 'Network unreachable';
+    act(() => {
+      tree!.update(<SubmitProofScreen />);
+    });
+    mockProofSubmitHook.submit.mockResolvedValue(undefined);
+
+    await pressButton(tree, 'Submit Proof');
+
+    const activity = useActivityStore.getState().activities[0]!;
+    expect(activity).toEqual(
+      expect.objectContaining({
+        taskId: 't1',
+        taskType: 'OTHER',
+        taskTitle: 'Task queued offline',
+        rewardAmount: 0,
+        rewardToken: 'ECO',
+        status: 'pending',
+      }),
+    );
+    expect(scheduleLocalNotification).not.toHaveBeenCalled();
+    expect(textValues(tree)).toContain('Network unreachable');
+  });
+
+  it('retake clears the preview and returns to capture mode', async () => {
+    tree = renderScreen();
+    await pressButton(tree, 'Take Photo');
+
+    expect(tree.root.findAllByType(Image).length).toBeGreaterThan(0);
+    expect(buttonByLabel(tree, 'Submit Proof')).toBeDefined();
+
+    await pressButton(tree, 'Retake');
+
+    expect(tree.root.findAllByType(Image)).toHaveLength(0);
+    expect(buttonByLabel(tree, 'Take Photo')).toBeDefined();
+    expect(buttonByLabel(tree, 'Submit Proof')).toBeUndefined();
+    expect(mockCameraTakePhoto).toHaveBeenCalledTimes(1);
+  });
+
+  it('shows a placeholder while the location is loading', () => {
+    mockLocation.location = null;
+    mockLocation.error = null;
+    tree = renderScreen();
+
+    expect(textValues(tree)).toContain('Getting location...');
+  });
+
+  it('shows the location error when location is unavailable', () => {
+    mockLocation.location = null;
+    mockLocation.error = 'Location permission denied';
+    tree = renderScreen();
+
+    expect(textValues(tree)).toContain('Location permission denied');
+  });
+
+  it('shows the uploading progress label', () => {
+    mockProofSubmitHook.progress = 'uploading';
+    tree = renderScreen();
+
+    expect(textValues(tree)).toContain('Uploading proof...');
+  });
+
+  it('shows the failed progress label', () => {
+    mockProofSubmitHook.progress = 'failed';
+    tree = renderScreen();
+
+    expect(textValues(tree)).toContain('Upload failed');
+  });
+
+  it('shows the confirmed progress label', () => {
+    mockProofSubmitHook.progress = 'confirmed';
+    tree = renderScreen();
+
+    expect(textValues(tree)).toContain('Reward confirmed!');
+  });
+
+  it('navigates back from the header', async () => {
+    tree = renderScreen();
+    await pressButton(tree, 'Back');
+
+    expect(mockGoBack).toHaveBeenCalled();
+  });
+});