diff --git a/apps/edr-freight-api/src/modules/first-mile/first-mile.service.ts b/apps/edr-freight-api/src/modules/first-mile/first-mile.service.ts
index 20048c94d..1a7db810d 100644
--- a/apps/edr-freight-api/src/modules/first-mile/first-mile.service.ts
+++ b/apps/edr-freight-api/src/modules/first-mile/first-mile.service.ts
@@ -1,5 +1,5 @@
-import { Injectable, Logger, NotFoundException } from '@nestjs/common';
-import { FindOptionsWhere, In } from 'typeorm';
+import { BadRequestException, Injectable, Logger, NotFoundException } from '@nestjs/common';
+import { FindOptionsWhere, In, IsNull, Not } from 'typeorm';
 import { InjectDataSource } from '@nestjs/typeorm';
 import { DataSource } from 'typeorm';
 import { VehicleAvailability } from '../vehicles/entities/vehicle.entity';
@@ -66,6 +66,19 @@ export class FirstMileService {
     }
   }
 
+  /** A leg counts as having a vehicle if it has a direct assignment or at least
+   *  one container allocation carrying a vehicle. Gates the IN_TRANSIT move. */
+  private async hasAssignedVehicle(
+    recordId: string,
+    directVehicleId?: string | null,
+  ): Promise<boolean> {
+    if (directVehicleId) return true;
+    const count = await this.dataSource.manager.count(FirstMileContainerAllocation, {
+      where: { firstMileId: recordId, vehicleId: Not(IsNull()) },
+    });
+    return count > 0;
+  }
+
   /** Human booking reference for a first-mile record, for the history timeline. */
   private async resolveBookingRef(record: FirstMile): Promise<string | null> {
     const loaded = (record as FirstMile & { booking?: { reference?: string } })
@@ -297,6 +310,18 @@ export class FirstMileService {
   async update(id: string, dto: UpdateFirstMileDto): Promise<FirstMile> {
     const existing = await this.findById(id);
 
+    // A leg can only go IN_TRANSIT once a vehicle is assigned (allowing a vehicle
+    // assigned in this same request).
+    if (dto.status === 'IN_TRANSIT' && existing.status !== 'IN_TRANSIT') {
+      const vehicleId =
+        dto.vehicleId !== undefined ? dto.vehicleId : existing.vehicleId;
+      if (!(await this.hasAssignedVehicle(id, vehicleId))) {
+        throw new BadRequestException(
+          'Assign a vehicle before marking this first-mile leg in transit',
+        );
+      }
+    }
+
     const dtoAny = dto as any;
     const updated = await this.firstMileRepository.update(id, {
       ...(dto.bookingId !== undefined ? { bookingId: dto.bookingId } : {}),
@@ -396,6 +421,15 @@ export class FirstMileService {
 
   async updateStatus(id: string, status: FirstMileStatus): Promise<FirstMile> {
     const existing = await this.findById(id);
+
+    if (status === 'IN_TRANSIT' && existing.status !== 'IN_TRANSIT') {
+      if (!(await this.hasAssignedVehicle(id, existing.vehicleId))) {
+        throw new BadRequestException(
+          'Assign a vehicle before marking this first-mile leg in transit',
+        );
+      }
+    }
+
     const updated = await this.firstMileRepository.update(id, { status });
 
     if (!updated) {
diff --git a/apps/edr-freight-api/src/modules/last-mile/last-mile.service.ts b/apps/edr-freight-api/src/modules/last-mile/last-mile.service.ts
index ade7402a9..884a02aae 100644
--- a/apps/edr-freight-api/src/modules/last-mile/last-mile.service.ts
+++ b/apps/edr-freight-api/src/modules/last-mile/last-mile.service.ts
@@ -1,5 +1,5 @@
-import { Injectable, Logger, NotFoundException } from '@nestjs/common';
-import { DataSource, FindOptionsWhere, In } from 'typeorm';
+import { BadRequestException, Injectable, Logger, NotFoundException } from '@nestjs/common';
+import { DataSource, FindOptionsWhere, In, IsNull, Not } from 'typeorm';
 
 import { BookingsRepository } from '../bookings/bookings.repository';
 import { DriversService } from '../drivers/drivers.service';
@@ -65,6 +65,19 @@ export class LastMileService {
     }
   }
 
+  /** A leg counts as having a vehicle if it has a direct assignment or at least
+   *  one container allocation carrying a vehicle. Gates the IN_TRANSIT move. */
+  private async hasAssignedVehicle(
+    recordId: string,
+    directVehicleId?: string | null,
+  ): Promise<boolean> {
+    if (directVehicleId) return true;
+    const count = await this.dataSource.manager.count(LastMileContainerAllocation, {
+      where: { lastMileId: recordId, vehicleId: Not(IsNull()) },
+    });
+    return count > 0;
+  }
+
   /** Human booking reference for a last-mile record, for the history timeline.
    *  Uses the already-loaded relation when present, else looks it up. */
   private async resolveBookingRef(
@@ -218,6 +231,18 @@ export class LastMileService {
   async update(id: string, dto: UpdateLastMileDto): Promise<LastMile> {
     const existing = await this.findById(id);
 
+    // A leg can only go IN_TRANSIT once a vehicle is assigned (allowing a vehicle
+    // assigned in this same request).
+    if (dto.status === 'IN_TRANSIT' && existing.status !== 'IN_TRANSIT') {
+      const vehicleId =
+        dto.vehicleId !== undefined ? dto.vehicleId : existing.vehicleId;
+      if (!(await this.hasAssignedVehicle(id, vehicleId))) {
+        throw new BadRequestException(
+          'Assign a vehicle before marking this last-mile leg in transit',
+        );
+      }
+    }
+
     const dtoAny = dto as any;
     const updated = await this.lastMileRepository.update(id, {
       ...(dto.bookingId !== undefined ? { bookingId: dto.bookingId } : {}),
diff --git a/apps/edr-freight-web/backoffice/src/pages/operations/FirstMilePage.tsx b/apps/edr-freight-web/backoffice/src/pages/operations/FirstMilePage.tsx
index cec4d4351..bbd5acc0c 100644
--- a/apps/edr-freight-web/backoffice/src/pages/operations/FirstMilePage.tsx
+++ b/apps/edr-freight-web/backoffice/src/pages/operations/FirstMilePage.tsx
@@ -879,10 +879,14 @@ const FirstMilePage = () => {
                 <Menu.Dropdown>
                   <Menu.Item
                     leftSection={<ArrowRight size={15} />}
-                    disabled={!nextStatus}
+                    disabled={!nextStatus || (nextStatus === "IN_TRANSIT" && !assigned)}
                     onClick={() => handleAdvanceStatus(row.original)}
                   >
-                    {nextStatus ? `Mark ${STATUS_META[nextStatus].label}` : STATUS_META[row.original.status].label}
+                    {nextStatus === "IN_TRANSIT" && !assigned
+                      ? "Assign a vehicle first"
+                      : nextStatus
+                        ? `Mark ${STATUS_META[nextStatus].label}`
+                        : STATUS_META[row.original.status].label}
                   </Menu.Item>
                   <Menu.Divider />
                   <Menu.Item
diff --git a/apps/edr-freight-web/backoffice/src/pages/operations/LastMilePage.tsx b/apps/edr-freight-web/backoffice/src/pages/operations/LastMilePage.tsx
index 7ec9d1b33..0a40e9d08 100644
--- a/apps/edr-freight-web/backoffice/src/pages/operations/LastMilePage.tsx
+++ b/apps/edr-freight-web/backoffice/src/pages/operations/LastMilePage.tsx
@@ -967,10 +967,14 @@ const LastMilePage = () => {
                 <Menu.Dropdown>
                   <Menu.Item
                     leftSection={<ArrowRight size={15} />}
-                    disabled={!nextStatus}
+                    disabled={!nextStatus || (nextStatus === "IN_TRANSIT" && !assigned)}
                     onClick={() => handleAdvanceStatus(row.original)}
                   >
-                    {nextStatus ? `Mark ${STATUS_META[nextStatus].label}` : STATUS_META[row.original.status].label}
+                    {nextStatus === "IN_TRANSIT" && !assigned
+                      ? "Assign a vehicle first"
+                      : nextStatus
+                        ? `Mark ${STATUS_META[nextStatus].label}`
+                        : STATUS_META[row.original.status].label}
                   </Menu.Item>
                   <Menu.Divider />
                   <Menu.Item