diff --git a/apps/api/src/planned/go.ts b/apps/api/src/planned/go.ts
index 56d97c91..008666d1 100644
--- a/apps/api/src/planned/go.ts
+++ b/apps/api/src/planned/go.ts
@@ -1,23 +1,16 @@
 /**
  * The Go of a planning (Ecrans E-07): « Étape suivante » marks a step done, and « Itinéraire »
- * opens Google Maps on foot to the next step only, never the whole route (D-029, D-032).
+ * opens Google Maps to the next step, in the mode of the trip that leads to it, never the whole
+ * route (D-029, D-032, #510).
  */
-import type { LatLng, PlannedMapsUrl, PlannedRoute } from '@widoo/shared';
+import { stepMapsUrl } from '@widoo/orchestration';
+import type { PlannedMapsUrl, PlannedRoute } from '@widoo/shared';
 import { and, asc, eq, isNull } from 'drizzle-orm';
 import type { Db } from '../db/client';
 import { plannedSteps } from '../db/schema';
 import { httpError } from '../errors';
 import { ownedPlanned, readPlanned, snapshotOfRow } from './repository';
 
-/** Google Maps URLs, on foot from where the phone is to `destination`. */
-export function walkingMapsUrl(destination: LatLng): string {
-  const url = new URL('https://www.google.com/maps/dir/');
-  url.searchParams.set('api', '1');
-  url.searchParams.set('destination', `${destination.lat},${destination.lng}`);
-  url.searchParams.set('travelmode', 'walking');
-  return url.href;
-}
-
 /** Marks a step of the caller's Go done, once: a skipped step becomes done. 409 outside a Go. */
 export async function markStepDone(
   db: Db,
@@ -58,9 +51,11 @@ export async function nextStepMapsUrl(db: Db, userId: string, id: string): Promi
     )
     .orderBy(asc(plannedSteps.position))
     .limit(1);
-  const step = snapshotOfRow(row).steps.find((candidate) => candidate.id === next?.stepId);
+  const steps = snapshotOfRow(row).steps;
+  const index = steps.findIndex((candidate) => candidate.id === next?.stepId);
+  const step = index === -1 ? undefined : steps[index];
   if (!step) {
     throw httpError(409, 'No step left to go to');
   }
-  return { stepId: step.id, url: walkingMapsUrl(step.place.location) };
+  return { stepId: step.id, url: stepMapsUrl(steps, index) };
 }
diff --git a/apps/api/src/routes/planned-go.test.ts b/apps/api/src/routes/planned-go.test.ts
index 38efa457..1401e284 100644
--- a/apps/api/src/routes/planned-go.test.ts
+++ b/apps/api/src/routes/planned-go.test.ts
@@ -1,11 +1,11 @@
 import { ApiError, PlannedMapsUrl, PlannedRoute } from '@widoo/shared';
+import { stepMapsUrl } from '@widoo/orchestration';
 import { and, eq } from 'drizzle-orm';
 import { afterAll, beforeAll, describe, expect, it } from 'vitest';
 import { buildApp } from '../app';
 import { TestTokenVerifier } from '../auth/test-verifier';
-import { plannedSteps } from '../db/schema';
+import { plannedSteps, steps } from '../db/schema';
 import { uuidv7 } from '../db/uuid';
-import { walkingMapsUrl } from '../planned/go';
 import { plannedFixtures, saturdayTen } from '../planned/test-fixtures';
 import { testConfig } from '../test-config';
 
@@ -24,13 +24,13 @@ afterAll(async () => {
 });
 
 type Headers = Record<string, string>;
-/** A planning of the caller, its Go started unless `isStarted` is false. */
-async function go(headers: Headers, isStarted = true) {
+/** A planning of the caller, its Go started unless `isStarted` is false; `route`'s plannable. */
+async function go(headers: Headers, isStarted = true, route = routeId) {
   const response = await app.inject({
     method: 'POST',
     url: '/v1/me/planned',
     headers,
-    payload: { routeId, startsAt: saturdayTen },
+    payload: { routeId: route, startsAt: saturdayTen },
   });
   const planned = PlannedRoute.parse(response.json());
   if (isStarted) {
@@ -49,18 +49,6 @@ const done = (headers: Headers, id: string, stepId: string | undefined, payload?
 const mapsUrl = (headers: Headers, id: string) =>
   app.inject({ url: `/v1/me/planned/${id}/maps-url`, headers });
 
-describe('walkingMapsUrl', () => {
-  it('builds a Google Maps URL on foot to one point', () => {
-    const url = new URL(walkingMapsUrl({ lat: 48.85661, lng: 2.35222 }));
-    expect(url.origin + url.pathname).toBe('https://www.google.com/maps/dir/');
-    expect(Object.fromEntries(url.searchParams)).toEqual({
-      api: '1',
-      destination: '48.85661,2.35222',
-      travelmode: 'walking',
-    });
-  });
-});
-
 describe('POST /v1/me/planned/:id/steps/:stepId/done', () => {
   it('marks a step done once, and a skipped step done', async () => {
     const headers = await fixtures.signIn();
@@ -104,26 +92,65 @@ describe('POST /v1/me/planned/:id/steps/:stepId/done', () => {
 });
 
 describe('GET /v1/me/planned/:id/maps-url', () => {
+  /** The destination of a Google Maps URL, decoded as the test compares it. */
+  const destinationOf = (url: string) => new URL(url).searchParams.get('destination');
+  /** The trip of each of the first three steps to the next one, and its Google Maps mode. */
+  const trips = [
+    ['bike', 'bicycling'],
+    ['metro', 'transit'],
+    ['car', 'driving'],
+  ] as const;
+
   it('opens Google Maps on foot to the next step only', async () => {
     const headers = await fixtures.signIn();
     const { id, route } = await go(headers);
     const [first, second] = route.steps;
+    const location = first?.place.location ?? { lat: 0, lng: 0 };
 
     const toFirst = PlannedMapsUrl.parse((await mapsUrl(headers, id)).json());
     expect(toFirst).toEqual({
       stepId: first?.id,
-      url: walkingMapsUrl(first?.place.location ?? { lat: 0, lng: 0 }),
+      url: `https://www.google.com/maps/dir/?api=1&destination=${encodeURIComponent(
+        `${location.lat},${location.lng}`,
+      )}&travelmode=walking`,
     });
     await done(headers, id, first?.id);
     const toSecond = PlannedMapsUrl.parse((await mapsUrl(headers, id)).json());
     expect(toSecond.stepId).toBe(second?.id);
-    const url = new URL(toSecond.url);
-    expect(url.searchParams.get('destination')).toBe(
+    expect(destinationOf(toSecond.url)).toBe(
       `${second?.place.location.lat},${second?.place.location.lng}`,
     );
-    expect(url.searchParams.get('travelmode')).toBe('walking');
-    // One destination, no waypoints: never the whole route.
-    expect(url.searchParams.has('waypoints')).toBe(false);
+    expect(toSecond.url).toContain('travelmode=walking');
+  });
+
+  it('opens Google Maps in the mode of the trip to the next steps, as the app does offline', async () => {
+    const headers = await fixtures.signIn();
+    const modeRoute = await fixtures.copyDemoRoute();
+    for (const [position, [mode]] of trips.entries()) {
+      await app.db
+        .update(steps)
+        .set({ transition: { distanceM: 900, durationMin: 10, mode, estimated: true } })
+        .where(and(eq(steps.routeId, modeRoute), eq(steps.position, position)));
+    }
+    const { id, route } = await go(headers, true, modeRoute);
+    // No trip of the route leads to the first step: on foot, even with a bike trip after it.
+    const toFirst = PlannedMapsUrl.parse((await mapsUrl(headers, id)).json());
+    expect(toFirst.url).toContain('travelmode=walking');
+    // The app, offline, writes the URL of the same step from the same planning (#510).
+    expect(toFirst.url).toBe(stepMapsUrl(route.steps, 0));
+    for (const [index, [, travelmode]] of trips.entries()) {
+      await done(headers, id, route.steps[index]?.id);
+      const next = route.steps[index + 1];
+      const answer = PlannedMapsUrl.parse((await mapsUrl(headers, id)).json());
+      expect(answer.stepId).toBe(next?.id);
+      expect(new URL(answer.url).searchParams.get('travelmode')).toBe(travelmode);
+      expect(answer.url).toBe(stepMapsUrl(route.steps, index + 1));
+      // One destination, the step's, and no waypoints: never the whole route (D-032).
+      expect(destinationOf(answer.url)).toBe(
+        `${next?.place.location.lat},${next?.place.location.lng}`,
+      );
+      expect(new URL(answer.url).searchParams.has('waypoints')).toBe(false);
+    }
   });
 
   it("answers 409 once every step is done, and 404 for another user's planning", async () => {
diff --git a/apps/api/src/routes/planned.ts b/apps/api/src/routes/planned.ts
index f43fe63b..36c4b783 100644
--- a/apps/api/src/routes/planned.ts
+++ b/apps/api/src/routes/planned.ts
@@ -139,7 +139,8 @@ export const plannedRoutesPlugin: FastifyPluginAsyncZod = async (app) => {
     {
       schema: {
         tags,
-        summary: 'Google Maps on foot to the next step of my planning, never the whole route',
+        summary:
+          'Google Maps to the next step of my planning, in the mode of the trip to it, never the whole route',
         security,
         params: PlannedParams,
         response: { 200: PlannedMapsUrl },
diff --git a/apps/mobile/src/go/progress.test.ts b/apps/mobile/src/go/progress.test.ts
index edfc437d..a9a2ee96 100644
--- a/apps/mobile/src/go/progress.test.ts
+++ b/apps/mobile/src/go/progress.test.ts
@@ -1,3 +1,4 @@
+import { stepMapsUrl } from '@widoo/orchestration';
 import { describe, expect, it } from 'vitest';
 import {
   actualMinutes,
@@ -6,7 +7,6 @@ import {
   emptyGoLocal,
   goProgress,
   isArrivalSuggested,
-  walkingMapsUrl,
 } from './progress';
 import { plannedFixture, stepIds } from './testPlanned';
 
@@ -104,10 +104,21 @@ describe('actualMinutes', () => {
   });
 });
 
-describe('walkingMapsUrl', () => {
-  it('writes Google Maps on foot to the step, as the API does', () => {
-    expect(walkingMapsUrl({ lat: 48.8674, lng: 2.3636 })).toBe(
+describe('maps URL', () => {
+  const planned = plannedFixture();
+
+  it('writes offline the URL the API writes, in the mode of the trip to the step', () => {
+    // « Itinéraire » offline builds the URL of `maps-url` with the same shared `stepMapsUrl`
+    // (#510): on foot to the first step, then in the mode of the trip that leads to it.
+    expect(stepMapsUrl(planned.route.steps, 0)).toBe(
       'https://www.google.com/maps/dir/?api=1&destination=48.8674%2C2.3636&travelmode=walking',
     );
+    expect(stepMapsUrl(planned.route.steps, 1)).toBe(
+      'https://www.google.com/maps/dir/?api=1&destination=48.8714%2C2.3676&travelmode=bicycling',
+    );
+    // The trip to the third step is by metro (its latitude, computed, is not a round literal).
+    expect(stepMapsUrl(planned.route.steps, 2)).toContain('travelmode=transit');
+    // One destination, no waypoints: never the whole route.
+    expect(stepMapsUrl(planned.route.steps, 2)).not.toContain('waypoints');
   });
 });
diff --git a/apps/mobile/src/go/progress.ts b/apps/mobile/src/go/progress.ts
index a4b1ebcb..18e9ed04 100644
--- a/apps/mobile/src/go/progress.ts
+++ b/apps/mobile/src/go/progress.ts
@@ -101,13 +101,3 @@ export function distanceToCurrent(progress: GoProgress, position: LatLng | null)
 /** The pill « Vous semblez être sur place »: en route, under 100 m of the step, app open. */
 export const isArrivalSuggested = (progress: GoProgress, distanceM: number | null) =>
   progress.phase === 'en_route' && distanceM !== null && distanceM < ARRIVAL_SUGGESTION_M;
-
-/** Google Maps on foot to `destination`, as the API writes it: « Itinéraire » offline (E-07). */
-export function walkingMapsUrl(destination: LatLng): string {
-  const query = new URLSearchParams({
-    api: '1',
-    destination: `${destination.lat},${destination.lng}`,
-    travelmode: 'walking',
-  });
-  return `https://www.google.com/maps/dir/?${query.toString()}`;
-}
diff --git a/apps/mobile/src/go/testPlanned.ts b/apps/mobile/src/go/testPlanned.ts
index 35b52d1c..244f73b7 100644
--- a/apps/mobile/src/go/testPlanned.ts
+++ b/apps/mobile/src/go/testPlanned.ts
@@ -15,6 +15,11 @@ const times = [
   ['09:00', '10:45'],
   ['11:00', '11:45'],
 ] as const;
+/** The trip of each step to the next one, in a mode of its own (#510); null for the last one. */
+const trips = [
+  { distanceM: 900, durationMin: 12, mode: 'bike', estimated: true },
+  { distanceM: 900, durationMin: 12, mode: 'metro', estimated: true },
+] as const;
 
 /**
  * A fictitious Go in progress of three steps near République, started at 10:00 in Paris; the
@@ -48,10 +53,7 @@ export function plannedFixture(
         bookingUrl: null,
         bookingProvider: null,
         transitionNote: null,
-        transition:
-          index < stepIds.length - 1
-            ? { distanceM: 900, durationMin: 12, mode: 'walk', estimated: true }
-            : null,
+        transition: trips[index] ?? null,
         place: {
           id,
           name: names[index] ?? 'Lieu fictif',
diff --git a/apps/mobile/src/go/useGo.ts b/apps/mobile/src/go/useGo.ts
index 4a84c840..dc127843 100644
--- a/apps/mobile/src/go/useGo.ts
+++ b/apps/mobile/src/go/useGo.ts
@@ -1,5 +1,6 @@
 import { onlineManager, useQuery, useQueryClient, type QueryClient } from '@tanstack/react-query';
 import { ApiRequestError } from '@widoo/api-client';
+import { stepMapsUrl } from '@widoo/orchestration';
 import type { PlannedRoute } from '@widoo/shared';
 import { router } from 'expo-router';
 import type { TFunction } from 'i18next';
@@ -18,14 +19,7 @@ import { plannedQueryKey, usePlannedLookup } from '../plan/planned';
 import { haptic } from '../ui/haptics';
 import { showToast } from '../ui/toastStore';
 import { createGoLocalStore } from './localStore';
-import {
-  actualMinutes,
-  doneRatio,
-  emptyGoLocal,
-  goProgress,
-  walkingMapsUrl,
-  type GoProgress,
-} from './progress';
+import { actualMinutes, doneRatio, emptyGoLocal, goProgress, type GoProgress } from './progress';
 import { startGo } from './startGo';
 
 const storage = createMMKV({ id: 'go' });
@@ -270,7 +264,10 @@ export function useGoActions(
         analytics.track('go_step_done', { route_id: routeId, step_index: current.index });
       }
     },
-    /** « Itinéraire »: Google Maps on foot to the step, by the API; written here offline. */
+    /**
+     * « Itinéraire »: Google Maps to the step, in the mode of the trip to it, by the API; written
+     * here offline with the same shared `stepMapsUrl` (E-07, #510).
+     */
     async directions() {
       if (!current) {
         return;
@@ -281,8 +278,8 @@ export function useGoActions(
           ? await api
               .getPlannedMapsUrl(planned.id)
               .then((answer) => answer.url)
-              .catch(() => walkingMapsUrl(current.step.place.location))
-          : walkingMapsUrl(current.step.place.location);
+              .catch(() => stepMapsUrl(planned.route.steps, current.index))
+          : stepMapsUrl(planned.route.steps, current.index);
       analytics.track('maps_opened', { route_id: routeId, mode: 'next_step' });
       await Linking.openURL(url).catch(failed);
     },
diff --git a/packages/api-client/src/client.ts b/packages/api-client/src/client.ts
index 7f0c6cb5..e84ff526 100644
--- a/packages/api-client/src/client.ts
+++ b/packages/api-client/src/client.ts
@@ -241,8 +241,9 @@ export function createApiClient(options: ApiClientOptions) {
       }),
 
     /**
-     * `GET /v1/me/planned/:id/maps-url`: « Itinéraire » of the Go, Google Maps on foot to the
-     * first step neither done nor skipped (D-032); 409 when none is left.
+     * `GET /v1/me/planned/:id/maps-url`: « Itinéraire » of the Go, Google Maps to the first step
+     * neither done nor skipped, in the mode of the trip that leads to it (D-032, #510); 409 when
+     * none is left.
      */
     getPlannedMapsUrl: (id: string, signal?: AbortSignal) =>
       request({
diff --git a/packages/orchestration/src/index.ts b/packages/orchestration/src/index.ts
index 15983588..d4b0fafc 100644
--- a/packages/orchestration/src/index.ts
+++ b/packages/orchestration/src/index.ts
@@ -9,6 +9,7 @@ export {
   type DirectionsProvider,
 } from './directions';
 export { COORDINATE_DECIMALS, roundedPoint, straightLineM } from './geo';
+export { stepMapsUrl, travelModeOf, type MapsStep, type MapsTravelMode } from './maps';
 export {
   computeTransitions,
   estimateOfMode,
diff --git a/packages/orchestration/src/maps.test.ts b/packages/orchestration/src/maps.test.ts
new file mode 100644
index 00000000..d83f3b7b
--- /dev/null
+++ b/packages/orchestration/src/maps.test.ts
@@ -0,0 +1,46 @@
+import { describe, expect, it } from 'vitest';
+import { stepMapsUrl, travelModeOf, type MapsStep } from './maps';
+
+/** Four steps near République, carrying the mode of each trip to the next one. */
+const steps = [
+  { place: { location: { lat: 48.8674, lng: 2.3636 } }, transition: { mode: 'bike' } },
+  { place: { location: { lat: 48.8714, lng: 2.3676 } }, transition: { mode: 'metro' } },
+  { place: { location: { lat: 48.8754, lng: 2.3716 } }, transition: { mode: 'car' } },
+  { place: { location: { lat: 48.8794, lng: 2.3756 } }, transition: null },
+] as const satisfies readonly MapsStep[];
+
+describe('travelModeOf', () => {
+  it('maps each transport to the travel mode of Google Maps', () => {
+    expect(travelModeOf('walk')).toBe('walking');
+    expect(travelModeOf('bike')).toBe('bicycling');
+    expect(travelModeOf('metro')).toBe('transit');
+    expect(travelModeOf('car')).toBe('driving');
+  });
+});
+
+describe('stepMapsUrl', () => {
+  it('opens the first step on foot, no trip of the route leads to it', () => {
+    expect(stepMapsUrl(steps, 0)).toBe(
+      'https://www.google.com/maps/dir/?api=1&destination=48.8674%2C2.3636&travelmode=walking',
+    );
+  });
+
+  it('opens the next steps in the mode of the trip that leads to them', () => {
+    expect(stepMapsUrl(steps, 1)).toContain('travelmode=bicycling');
+    expect(stepMapsUrl(steps, 2)).toContain('travelmode=transit');
+    expect(stepMapsUrl(steps, 3)).toContain('travelmode=driving');
+  });
+
+  it('opens on foot a step whose trip carries no mode', () => {
+    const modeless = [
+      { place: { location: { lat: 48.8674, lng: 2.3636 } }, transition: null },
+      { place: { location: { lat: 48.8714, lng: 2.3676 } }, transition: null },
+    ] as const satisfies readonly MapsStep[];
+    expect(stepMapsUrl(modeless, 1)).toContain('travelmode=walking');
+  });
+
+  it('always takes one destination, never the whole route', () => {
+    expect(stepMapsUrl(steps, 2)).toContain('destination=48.8754%2C2.3716&');
+    expect(stepMapsUrl(steps, 2)).not.toContain('waypoints');
+  });
+});
diff --git a/packages/orchestration/src/maps.ts b/packages/orchestration/src/maps.ts
new file mode 100644
index 00000000..40e4feb4
--- /dev/null
+++ b/packages/orchestration/src/maps.ts
@@ -0,0 +1,50 @@
+/**
+ * Google Maps of « Itinéraire » (Ecrans › E-07): the command opens Google Maps to the step to go
+ * to, in the mode of the trip that leads to it (#510, D-052). One definition, shared by
+ * `GET /v1/me/planned/:id/maps-url` and by the app when the network is down.
+ */
+import type { LatLng, Transport } from '@widoo/shared';
+
+/** The travel mode of Google Maps: the value of `travelmode=`, never a display label. */
+export type MapsTravelMode = 'walking' | 'bicycling' | 'transit' | 'driving';
+
+/**
+ * The travel mode of Google Maps for a trip in each transport: the `mappings.transitModes` table
+ * of `packages/tokens/generated/tokens.json` (`walk` → `walking`, `bike` → `bicycling`, `metro` →
+ * `transit`, `car` → `driving`), defined here because the tokens package does not export it.
+ */
+const travelModeOfTransport: Record<Transport, MapsTravelMode> = {
+  walk: 'walking',
+  bike: 'bicycling',
+  metro: 'transit',
+  car: 'driving',
+};
+
+/** The travel mode of Google Maps for a trip in this transport. */
+export function travelModeOf(transport: Transport): MapsTravelMode {
+  return travelModeOfTransport[transport];
+}
+
+/** A step as the URL needs it: where to go, and the trip from it to the next one. */
+export interface MapsStep {
+  place: { location: LatLng };
+  /** The trip to the next step; null for the last one (`Step.transition`). */
+  transition: { mode: Transport } | null;
+}
+
+/**
+ * Google Maps to the step at this index of the snapshot, in the mode of the trip to it: no trip
+ * leads to the first step, so Google Maps opens it on foot, and so again when the trip carries
+ * no mode. One URL for one step, never for the whole route (D-032).
+ */
+export function stepMapsUrl(steps: readonly MapsStep[], index: number): string {
+  const step = steps[index];
+  if (!step) {
+    throw new Error(`No step at index ${index}`);
+  }
+  const transition = index > 0 ? steps[index - 1]?.transition : null;
+  const travelmode = transition ? travelModeOf(transition.mode) : 'walking';
+  return `https://www.google.com/maps/dir/?api=1&destination=${encodeURIComponent(
+    `${step.place.location.lat},${step.place.location.lng}`,
+  )}&travelmode=${travelmode}`;
+}