diff --git a/apps/edr-freight-api/src/modules/auth/check-availability.controller.ts b/apps/edr-freight-api/src/modules/auth/check-availability.controller.ts
new file mode 100644
index 000000000..13084d1c8
--- /dev/null
+++ b/apps/edr-freight-api/src/modules/auth/check-availability.controller.ts
@@ -0,0 +1,22 @@
+import { Controller, Get, Query } from "@nestjs/common";
+import { ApiOperation, ApiTags } from "@nestjs/swagger";
+import { Public } from "@edr/api-common";
+
+import { CheckAvailabilityService } from "./check-availability.service";
+
+@ApiTags("auth")
+@Controller("auth")
+@Public()
+export class CheckAvailabilityController {
+  constructor(
+    private readonly checkAvailabilityService: CheckAvailabilityService,
+  ) {}
+
+  @Get("check-availability")
+  @ApiOperation({
+    summary: "Check whether an email and/or phone number is already registered",
+  })
+  check(@Query("email") email?: string, @Query("phone") phone?: string) {
+    return this.checkAvailabilityService.check({ email, phone });
+  }
+}
diff --git a/apps/edr-freight-api/src/modules/auth/check-availability.service.ts b/apps/edr-freight-api/src/modules/auth/check-availability.service.ts
new file mode 100644
index 000000000..c9ce84b72
--- /dev/null
+++ b/apps/edr-freight-api/src/modules/auth/check-availability.service.ts
@@ -0,0 +1,47 @@
+import { BadRequestException, Injectable } from "@nestjs/common";
+import { InjectRepository } from "@nestjs/typeorm";
+import { Repository } from "typeorm";
+
+import { User } from "@tria-plc/iamapi-common/entities/iam/user/user.entity";
+
+export interface CheckAvailabilityQuery {
+  email?: string;
+  phone?: string;
+}
+
+export interface CheckAvailabilityResult {
+  emailTaken: boolean;
+  phoneTaken: boolean;
+}
+
+@Injectable()
+export class CheckAvailabilityService {
+  constructor(
+    @InjectRepository(User)
+    private readonly userRepository: Repository<User>,
+  ) {}
+
+  async check({
+    email,
+    phone,
+  }: CheckAvailabilityQuery): Promise<CheckAvailabilityResult> {
+    if (!email && !phone) {
+      throw new BadRequestException("email or phone is required");
+    }
+
+    const matches = await this.userRepository.find({
+      where: [
+        ...(email ? [{ email }] : []),
+        ...(phone ? [{ phoneNumber: phone }] : []),
+      ],
+      select: { id: true, email: true, phoneNumber: true },
+    });
+
+    return {
+      emailTaken: email ? matches.some((user) => user.email === email) : false,
+      phoneTaken: phone
+        ? matches.some((user) => user.phoneNumber === phone)
+        : false,
+    };
+  }
+}
diff --git a/apps/edr-freight-api/src/modules/auth/freight-auth.module.ts b/apps/edr-freight-api/src/modules/auth/freight-auth.module.ts
index a689ba24e..16fbeffda 100644
--- a/apps/edr-freight-api/src/modules/auth/freight-auth.module.ts
+++ b/apps/edr-freight-api/src/modules/auth/freight-auth.module.ts
@@ -1,10 +1,16 @@
 import { Module } from '@nestjs/common';
+import { TypeOrmModule } from '@nestjs/typeorm';
 
+import { User } from '@tria-plc/iamapi-common/entities/iam/user/user.entity';
+
+import { CheckAvailabilityController } from './check-availability.controller';
+import { CheckAvailabilityService } from './check-availability.service';
 import { FreightMeController } from './freight-me.controller';
 import { FreightMeService } from './freight-me.service';
 
 @Module({
-  controllers: [FreightMeController],
-  providers: [FreightMeService],
+  imports: [TypeOrmModule.forFeature([User])],
+  controllers: [FreightMeController, CheckAvailabilityController],
+  providers: [FreightMeService, CheckAvailabilityService],
 })
 export class FreightAuthModule {}
diff --git a/apps/edr-freight-web/portal/src/constants/URLS.ts b/apps/edr-freight-web/portal/src/constants/URLS.ts
index a4e20b029..a8cafc0d1 100644
--- a/apps/edr-freight-web/portal/src/constants/URLS.ts
+++ b/apps/edr-freight-web/portal/src/constants/URLS.ts
@@ -14,6 +14,7 @@ export const URL_CONSTANTS = {
     SET_PASSWORD: "/api/auth/set-password",
     ME: "/api/auth/me",
     GENERATE_VERIFICATION_CODE: "/users/generate-verification-code",
+    CHECK_AVAILABILITY: "/api/auth/check-availability",
   },
 
   OTP: {
diff --git a/apps/edr-freight-web/portal/src/pages/accounts/SignupPage.tsx b/apps/edr-freight-web/portal/src/pages/accounts/SignupPage.tsx
index 50320f699..05fa411b5 100644
--- a/apps/edr-freight-web/portal/src/pages/accounts/SignupPage.tsx
+++ b/apps/edr-freight-web/portal/src/pages/accounts/SignupPage.tsx
@@ -132,12 +132,30 @@ export default function SignupPage() {
 
   const passwordValue = watch("password") ?? "";
 
-  // Step 1 — form is valid: send a fresh code to the chosen channel, then
-  // move to the OTP challenge.
+  // Step 1 — form is valid: make sure the email/phone aren't already
+  // registered, then send a fresh code to the chosen channel and move to
+  // the OTP challenge.
   const requestOtp = async (data: FormData) => {
     setError(null);
     setSending(true);
     try {
+      const availability = await api.auth.checkAvailability.call({
+        email: data.email,
+        phone: data.phone,
+      });
+      if (availability.emailTaken && availability.phoneTaken) {
+        setError("An account with this email and phone number already exists.");
+        return;
+      }
+      if (availability.emailTaken) {
+        setError("An account with this email already exists.");
+        return;
+      }
+      if (availability.phoneTaken) {
+        setError("An account with this phone number already exists.");
+        return;
+      }
+
       await api.auth.sendOTP.call(
         channel === "email" ? { email: data.email } : { phone: data.phone },
       );
diff --git a/apps/edr-freight-web/portal/src/services/api.ts b/apps/edr-freight-web/portal/src/services/api.ts
index 81a2488a9..932f6fc46 100644
--- a/apps/edr-freight-web/portal/src/services/api.ts
+++ b/apps/edr-freight-web/portal/src/services/api.ts
@@ -66,6 +66,8 @@ import type {
 import type { ProfileResponse, UpdateProfilePayload } from "@/types/profile";
 import type {
   AuthUser,
+  CheckAvailabilityPayload,
+  CheckAvailabilityResponse,
   GenerateVerificationCodePayload,
   LoginPayload,
   LoginResponse,
@@ -107,6 +109,11 @@ export const api = {
       "setPassword",
       authService.setPassword,
     ),
+    checkAvailability: endpoint<CheckAvailabilityPayload, CheckAvailabilityResponse>(
+      "auth",
+      "checkAvailability",
+      authService.checkAvailability,
+    ),
     sendOTP: endpoint<OtpPayload, OtpResponse>(
       "auth",
       "sendOTP",
diff --git a/apps/edr-freight-web/portal/src/services/auth.service.ts b/apps/edr-freight-web/portal/src/services/auth.service.ts
index e1de1889a..58b81c5ba 100644
--- a/apps/edr-freight-web/portal/src/services/auth.service.ts
+++ b/apps/edr-freight-web/portal/src/services/auth.service.ts
@@ -1,14 +1,16 @@
 import { URL_CONSTANTS } from "@/constants/URLS";
 import type {
-    AuthUser,
-    GenerateVerificationCodePayload,
-    LoginPayload,
-    LoginResponse,
-    OtpPayload,
-    OtpResponse,
-    SetPasswordPayload,
-    SignupPayload,
-    SignupResponse,
+  AuthUser,
+  CheckAvailabilityPayload,
+  CheckAvailabilityResponse,
+  GenerateVerificationCodePayload,
+  LoginPayload,
+  LoginResponse,
+  OtpPayload,
+  OtpResponse,
+  SetPasswordPayload,
+  SignupPayload,
+  SignupResponse,
 } from "@/types/auth";
 import { client } from "@/utils/api";
 import { ApiResponse } from "@edr/types";
@@ -23,7 +25,7 @@ export const authService = {
   },
 
   createUser: async (body: SignupPayload) => {
-    const res = await client.post<SignupResponse & ApiResponse<void>> (
+    const res = await client.post<SignupResponse & ApiResponse<void>>(
       URL_CONSTANTS.USERS.SIGN_UP,
       body,
     );
@@ -31,9 +33,7 @@ export const authService = {
   },
 
   getMyInfo: async () => {
-    const res = await client.get<AuthUser>(
-      URL_CONSTANTS.USERS.ME,
-    );
+    const res = await client.get<AuthUser>(URL_CONSTANTS.USERS.ME);
     return res.data;
   },
 
@@ -53,6 +53,14 @@ export const authService = {
     return res.data.data;
   },
 
+  checkAvailability: async (params: CheckAvailabilityPayload) => {
+    const res = await client.get<ApiResponse<CheckAvailabilityResponse>>(
+      URL_CONSTANTS.USERS.CHECK_AVAILABILITY,
+      { params },
+    );
+    return res.data;
+  },
+
   sendOTP: async (body: OtpPayload) => {
     const res = await client.post<ApiResponse<OtpResponse>>(
       URL_CONSTANTS.OTP.SEND,
diff --git a/apps/edr-freight-web/portal/src/types/auth.ts b/apps/edr-freight-web/portal/src/types/auth.ts
index 7b58f573b..04357a9ca 100644
--- a/apps/edr-freight-web/portal/src/types/auth.ts
+++ b/apps/edr-freight-web/portal/src/types/auth.ts
@@ -45,6 +45,16 @@ export interface OtpResponse {
   message: string;
 }
 
+export interface CheckAvailabilityPayload {
+  email?: string;
+  phone?: string;
+}
+
+export interface CheckAvailabilityResponse {
+  emailTaken: boolean;
+  phoneTaken: boolean;
+}
+
 export interface SetPasswordPayload {
   newPassword: string;
   confirmPassword: string;