diff --git a/apps/web/src/features/scenario-creator/components/Area3DView.tsx b/apps/web/src/features/scenario-creator/components/Area3DView.tsx
new file mode 100644
index 0000000..b0c3f84
--- /dev/null
+++ b/apps/web/src/features/scenario-creator/components/Area3DView.tsx
@@ -0,0 +1,119 @@
+import { Suspense, useMemo, useRef, useEffect } from 'react'
+import { Canvas, useThree } from '@react-three/fiber'
+import { useGLTF, Clone } from '@react-three/drei'
+import * as THREE from 'three'
+import { useScenarioStore } from '../store'
+import { useSimulationStore } from '../../../stores/simulationStore'
+import { useVesselPanelStore } from '../../../stores/vesselPanelStore'
+import { AREA_ROT_X, simToScene, headingToSceneYaw } from '../../../lib/geo3d'
+import { tokens } from '../../../theme/tokens'
+
+const AREA_BASE = '/assets/3d/baia_de_guanabara'
+const VESSEL_URL = '/assets/3d/vessel/celso_furtado.glb'
+const AREA_PARTS = [`${AREA_BASE}/batimetria.glb`, `${AREA_BASE}/ilhas.glb`, `${AREA_BASE}/ponte.glb`]
+
+// Onboard "Front" camera offset from vessel_config (local metres, vessel frame).
+const FRONT_CAM = { x: 0, y: 31.5, z: -58.8 }
+
+/** The Baía meshes are Z-up; rotate to Y-up and recentre horizontally on the sim
+ *  origin so vessels (near 0,0) sit on the bay. */
+function AreaScene() {
+  const group = useRef<THREE.Group>(null)
+  const parts = AREA_PARTS.map((u) => useGLTF(u))
+
+  useEffect(() => {
+    const g = group.current
+    if (!g) return
+    // Recentre on the horizontal bounding-box centre (keep vertical as-is).
+    const box = new THREE.Box3().setFromObject(g)
+    const c = box.getCenter(new THREE.Vector3())
+    g.position.x -= c.x
+    g.position.z -= c.z
+  }, [])
+
+  return (
+    <group ref={group} rotation={[AREA_ROT_X, 0, 0]}>
+      {parts.map((p, i) => (
+        <primitive key={i} object={p.scene} />
+      ))}
+    </group>
+  )
+}
+
+function VesselModel({ x, y, headingDeg }: { x: number; y: number; headingDeg: number }) {
+  const { scene } = useGLTF(VESSEL_URL)
+  const [px, py, pz] = simToScene(x, y)
+  return (
+    <group position={[px, py, pz]} rotation={[0, headingToSceneYaw((headingDeg * Math.PI) / 180), 0]}>
+      <Clone object={scene} />
+    </group>
+  )
+}
+
+/** Camera anchored to the selected vessel's onboard Front camera; falls back to a
+ *  bay overview when nothing is selected. */
+function CameraRig({ target }: { target: { x: number; y: number; headingDeg: number } | null }) {
+  const { camera } = useThree()
+  useEffect(() => {
+    if (!target) {
+      camera.position.set(0, 1200, 1800)
+      camera.lookAt(0, 0, 0)
+      return
+    }
+    const yaw = headingToSceneYaw((target.headingDeg * Math.PI) / 180)
+    const [bx, by, bz] = simToScene(target.x, target.y)
+    // Place the camera at the Front offset rotated into world space.
+    const off = new THREE.Vector3(FRONT_CAM.x, FRONT_CAM.y, FRONT_CAM.z)
+    off.applyAxisAngle(new THREE.Vector3(0, 1, 0), yaw)
+    camera.position.set(bx + off.x, by + off.y, bz + off.z)
+    // Look level toward the horizon along the vessel heading (out the bridge),
+    // not down at the console.
+    const ahead = new THREE.Vector3(0, -250, -1500).applyAxisAngle(new THREE.Vector3(0, 1, 0), yaw)
+    camera.lookAt(bx + off.x + ahead.x, by + off.y + ahead.y, bz + off.z + ahead.z)
+  }, [camera, target])
+  return null
+}
+
+export function Area3DView() {
+  const { vessels } = useScenarioStore()
+  const { status, state } = useSimulationStore()
+  const { selectedVesselId } = useVesselPanelStore()
+  const running = status === 'running' || status === 'paused'
+
+  // Resolve each vessel's current pose (live state while running, draft otherwise).
+  const posed = useMemo(() => vessels.map((v) => {
+    const live = running ? state?.vessels.find((s) => s.id === v.instanceId) : null
+    return live
+      ? { instanceId: v.instanceId, x: live.x, y: live.y, headingDeg: (live.psi * 180) / Math.PI }
+      : { instanceId: v.instanceId, x: v.x, y: v.y, headingDeg: v.headingDeg }
+  }), [vessels, running, state])
+
+  const target = posed.find((p) => p.instanceId === selectedVesselId) ?? posed[0] ?? null
+
+  return (
+    <Canvas
+      camera={{ fov: 55, near: 1, far: 100000, position: [0, 1200, 1800] }}
+      style={{ width: '100%', height: '100%', background: '#0b1f33' }}
+      data-testid="area-3d-view"
+    >
+      <ambientLight intensity={0.6} />
+      <hemisphereLight args={['#bcd8ff', '#24435f', 1.2]} />
+      <directionalLight position={[5000, 8000, 4000]} intensity={2.2} />
+      <Suspense fallback={null}>
+        <AreaScene />
+        {posed.map((p) => (
+          <VesselModel key={p.instanceId} x={p.x} y={p.y} headingDeg={p.headingDeg} />
+        ))}
+      </Suspense>
+      {/* Water plane at sea level. */}
+      <mesh rotation={[-Math.PI / 2, 0, 0]} position={[0, 0, 0]}>
+        <planeGeometry args={[80000, 80000]} />
+        <meshStandardMaterial color={tokens.color.accent} transparent opacity={0.55} />
+      </mesh>
+      <CameraRig target={target} />
+    </Canvas>
+  )
+}
+
+AREA_PARTS.forEach((u) => useGLTF.preload(u))
+useGLTF.preload(VESSEL_URL)
diff --git a/apps/web/src/features/scenario-creator/components/ViewToggle.test.tsx b/apps/web/src/features/scenario-creator/components/ViewToggle.test.tsx
new file mode 100644
index 0000000..113ca16
--- /dev/null
+++ b/apps/web/src/features/scenario-creator/components/ViewToggle.test.tsx
@@ -0,0 +1,22 @@
+import { render, screen, fireEvent } from '@testing-library/react'
+import { describe, it, expect, beforeEach } from 'vitest'
+import { ViewToggle } from './ViewToggle'
+import { useViewStore } from '../../../stores/viewStore'
+
+describe('ViewToggle', () => {
+  beforeEach(() => useViewStore.setState({ mode: 'map' }))
+
+  it('defaults to Mapa selected', () => {
+    render(<ViewToggle />)
+    expect(screen.getByRole('button', { name: 'Mapa' })).toHaveAttribute('aria-pressed', 'true')
+    expect(screen.getByRole('button', { name: '3D' })).toHaveAttribute('aria-pressed', 'false')
+  })
+
+  it('switches to 3D and back', () => {
+    render(<ViewToggle />)
+    fireEvent.click(screen.getByRole('button', { name: '3D' }))
+    expect(useViewStore.getState().mode).toBe('3d')
+    fireEvent.click(screen.getByRole('button', { name: 'Mapa' }))
+    expect(useViewStore.getState().mode).toBe('map')
+  })
+})
diff --git a/apps/web/src/features/scenario-creator/components/ViewToggle.tsx b/apps/web/src/features/scenario-creator/components/ViewToggle.tsx
new file mode 100644
index 0000000..92b748a
--- /dev/null
+++ b/apps/web/src/features/scenario-creator/components/ViewToggle.tsx
@@ -0,0 +1,44 @@
+import type { CSSProperties } from 'react'
+import { useViewStore, type ViewMode } from '../../../stores/viewStore'
+import { tokens } from '../../../theme/tokens'
+
+/** Segmented control (top-left of the workspace) to switch the background between
+ *  the 2D map and the 3D scene. Panels are unaffected. */
+export function ViewToggle() {
+  const { mode, setMode } = useViewStore()
+
+  const seg = (m: ViewMode, label: string): CSSProperties => ({
+    padding: `${tokens.space.xs}px ${tokens.space.md}px`,
+    border: 'none',
+    background: mode === m ? tokens.color.accent : 'transparent',
+    color: mode === m ? tokens.color.textOnDark : tokens.color.textSecondary,
+    fontFamily: tokens.font.sans,
+    fontSize: tokens.fontSize.label,
+    fontWeight: tokens.fontWeight.medium,
+    cursor: 'pointer',
+    borderRadius: tokens.radius.pill,
+  })
+
+  return (
+    <div
+      role="group"
+      aria-label="Visualização"
+      style={{
+        position: 'absolute',
+        top: tokens.space.lg,
+        left: tokens.space.lg,
+        display: 'inline-flex',
+        gap: 2,
+        padding: 2,
+        background: tokens.color.surface,
+        border: `1px solid ${tokens.color.border}`,
+        borderRadius: tokens.radius.pill,
+        boxShadow: tokens.shadow.sm,
+        zIndex: tokens.z.panel,
+      }}
+    >
+      <button type="button" style={seg('map', 'Mapa')} aria-pressed={mode === 'map'} onClick={() => setMode('map')}>Mapa</button>
+      <button type="button" style={seg('3d', '3D')} aria-pressed={mode === '3d'} onClick={() => setMode('3d')}>3D</button>
+    </div>
+  )
+}
diff --git a/apps/web/src/features/shell/AppShell.test.tsx b/apps/web/src/features/shell/AppShell.test.tsx
index d08ad11..2bba566 100644
--- a/apps/web/src/features/shell/AppShell.test.tsx
+++ b/apps/web/src/features/shell/AppShell.test.tsx
@@ -5,10 +5,13 @@ import { AppShell } from './AppShell'
 import { useScenarioStore } from '../scenario-creator/store'
 import { useSimulationStore } from '../../stores/simulationStore'
 
-// Leaflet map can't render in jsdom — stub the map surface (covered by e2e).
+// Leaflet map + Three canvas can't render in jsdom — stub both backgrounds.
 vi.mock('../scenario-creator/components/AreaMapView', () => ({
   AreaMapView: () => <div data-testid="map" />,
 }))
+vi.mock('../scenario-creator/components/Area3DView', () => ({
+  Area3DView: () => <div data-testid="area-3d-view" />,
+}))
 
 vi.stubGlobal('Worker', class {
   onmessage: ((e: MessageEvent) => void) | null = null
diff --git a/apps/web/src/features/shell/AppShell.tsx b/apps/web/src/features/shell/AppShell.tsx
index a23e050..2acb318 100644
--- a/apps/web/src/features/shell/AppShell.tsx
+++ b/apps/web/src/features/shell/AppShell.tsx
@@ -8,12 +8,15 @@ import { MapActions } from '../../ui/MapActions'
 import { AlertDialog } from '../../ui/Modal'
 import { Sidebar } from '../scenario-creator/components/Sidebar'
 import { AreaMapView } from '../scenario-creator/components/AreaMapView'
+import { Area3DView } from '../scenario-creator/components/Area3DView'
+import { ViewToggle } from '../scenario-creator/components/ViewToggle'
 import { VesselPanel } from '../scenario-creator/components/VesselPanel'
 import { VesselPicker } from '../scenario-creator/components/VesselPicker'
 import { ScenarioInfoPanel } from '../scenario-info/ScenarioInfoPanel'
 import { useScenarioStore } from '../scenario-creator/store'
 import { useSimulationStore } from '../../stores/simulationStore'
 import { useMapStore } from '../../stores/mapStore'
+import { useViewStore } from '../../stores/viewStore'
 import { tokens } from '../../theme/tokens'
 
 const API_BASE = import.meta.env.VITE_API_URL ?? 'http://localhost:3000'
@@ -27,6 +30,7 @@ export function AppShell() {
   const { name, vessels, setName, toCreateScenarioDTO } = useScenarioStore()
   const { status, state, scenarioVessels, play, pause, loadScenario, applyEnvironment } = useSimulationStore()
   const { zoomIn, zoomOut } = useMapStore()
+  const { mode } = useViewStore()
   const [confirmNoOwnship, setConfirmNoOwnship] = useState(false)
   const [infoOpen, setInfoOpen] = useState(false)
   const [pickerOpen, setPickerOpen] = useState(false)
@@ -127,10 +131,11 @@ export function AppShell() {
       <div style={{ flex: 1, display: 'flex', minHeight: 0 }}>
         <Sidebar />
         <div style={{ flex: 1, position: 'relative' }}>
-          <AreaMapView />
+          {mode === 'map' ? <AreaMapView /> : <Area3DView />}
+          <ViewToggle />
           <VesselPanel />
           <ScenarioInfoPanel open={infoOpen} onClose={() => setInfoOpen(false)} />
-          <MapActions onZoomIn={zoomIn} onZoomOut={zoomOut} />
+          {mode === 'map' && <MapActions onZoomIn={zoomIn} onZoomOut={zoomOut} />}
           <SimulationControl
             running={status === 'running'}
             disabled={vessels.length === 0}
diff --git a/apps/web/src/lib/geo3d.test.ts b/apps/web/src/lib/geo3d.test.ts
new file mode 100644
index 0000000..ec25e8b
--- /dev/null
+++ b/apps/web/src/lib/geo3d.test.ts
@@ -0,0 +1,25 @@
+import { describe, it, expect } from 'vitest'
+import { simToScene, headingToSceneYaw, AREA_ROT_X } from './geo3d'
+
+describe('geo3d', () => {
+  it('maps sim origin to the scene origin', () => {
+    expect(simToScene(0, 0)).toEqual([0, 0, 0])
+  })
+
+  it('maps East to +X and North to -Z', () => {
+    expect(simToScene(100, 0)).toEqual([100, 0, 0]) // East
+    expect(simToScene(0, 100)).toEqual([0, 0, -100]) // North → -Z
+  })
+
+  it('keeps an optional height on the Y axis', () => {
+    expect(simToScene(10, 20, 5)).toEqual([10, 5, -20])
+  })
+
+  it('passes heading through as the scene yaw', () => {
+    expect(headingToSceneYaw(Math.PI / 2)).toBeCloseTo(Math.PI / 2)
+  })
+
+  it('rotates the Z-up area meshes a quarter-turn onto Y-up', () => {
+    expect(AREA_ROT_X).toBeCloseTo(-Math.PI / 2)
+  })
+})
diff --git a/apps/web/src/lib/geo3d.ts b/apps/web/src/lib/geo3d.ts
new file mode 100644
index 0000000..798f760
--- /dev/null
+++ b/apps/web/src/lib/geo3d.ts
@@ -0,0 +1,28 @@
+/**
+ * Maps the simulation's local frame (metres, x=East, y=North, ψ=heading as a math
+ * angle: 0=East, CCW positive) into the Three.js scene (Y-up, right-handed).
+ *
+ * The Baía de Guanabara meshes are exported Z-up (the thin vertical axis is Z),
+ * so the area group is rotated -90° about X to bring Z→Y. After that rotation the
+ * horizontal plane is X (East) / Z, with North pointing along -Z. Hence:
+ *   sceneX =  x(East)        sceneZ = -y(North)        sceneY = up
+ *
+ * Sign/offset constants are isolated here so the scene can be calibrated against a
+ * known landmark (e.g. the Rio-Niterói bridge) without touching component code.
+ */
+export const AREA_ROT_X = -Math.PI / 2 // rotate area meshes from Z-up to Y-up
+
+/** Convert sim ground coordinates (metres) to a Three.js position on the water plane. */
+export function simToScene(x: number, y: number, height = 0): [number, number, number] {
+  return [x, height, 0 - y] // `0 - y` avoids a negative-zero on the North axis
+}
+
+/**
+ * Convert a sim heading ψ (radians, 0=East, CCW) to a Three.js Y-axis rotation.
+ * In the scene, +X is East and -Z is North; a yaw of 0 should point the model East.
+ * Three's Y rotation is CCW looking down the +Y axis, which corresponds to the
+ * East→North sense after the Z flip, so the heading maps directly.
+ */
+export function headingToSceneYaw(psiRad: number): number {
+  return psiRad
+}
diff --git a/apps/web/src/stores/viewStore.ts b/apps/web/src/stores/viewStore.ts
new file mode 100644
index 0000000..551bdc9
--- /dev/null
+++ b/apps/web/src/stores/viewStore.ts
@@ -0,0 +1,17 @@
+import { create } from 'zustand'
+
+export type ViewMode = 'map' | '3d'
+
+interface ViewStore {
+  mode: ViewMode
+  setMode: (m: ViewMode) => void
+  toggle: () => void
+}
+
+/** Which background the scenario workspace shows — 2D map or the 3D scene.
+ *  Only the background swaps; all panels are shared. */
+export const useViewStore = create<ViewStore>((set, get) => ({
+  mode: 'map',
+  setMode: (mode) => set({ mode }),
+  toggle: () => set({ mode: get().mode === 'map' ? '3d' : 'map' }),
+}))
diff --git a/apps/web/vitest.config.ts b/apps/web/vitest.config.ts
index 7b526e3..b77a923 100644
--- a/apps/web/vitest.config.ts
+++ b/apps/web/vitest.config.ts
@@ -21,9 +21,10 @@ export default defineConfig({
         'src/App.tsx',
         'src/**/*.d.ts',
         'src/**/index.ts',
-        // Leaflet components — require canvas/browser, tested via E2E
+        // Leaflet + Three.js scene components — require canvas/WebGL, tested via E2E
         'src/features/scenario-creator/components/AreaMapView.tsx',
         'src/features/scenario-creator/components/VesselMarker.tsx',
+        'src/features/scenario-creator/components/Area3DView.tsx',
         // Pure layout composition — no logic to unit test
         'src/features/scenario-creator/components/Sidebar.tsx',
         // Web Workers — not runnable in jsdom