diff --git a/src/languages/de.ts b/src/languages/de.ts
index a6cf5c09960f..33e0a05271a0 100644
--- a/src/languages/de.ts
+++ b/src/languages/de.ts
@@ -2955,6 +2955,8 @@ ${amount} für ${merchant} – ${date}`,
         phoneOrEmail: 'Telefon oder E-Mail',
         error: {
             invalidFormatEmailLogin: 'Die eingegebene E-Mail-Adresse ist ungültig. Bitte korrigiere das Format und versuche es erneut.',
+            agentSignInBlocked:
+                'Agent-Konten können nicht direkt verwendet werden. Um ein Agent-Konto zu nutzen, melden Sie sich mit Ihrem eigenen Konto an und greifen Sie über Copilot darauf zu.',
         },
         cannotGetAccountDetails: 'Kontodetails konnten nicht abgerufen werden. Bitte melde dich erneut an.',
         loginForm: 'Anmeldeformular',
diff --git a/src/languages/en.ts b/src/languages/en.ts
index 0b50e1b7b55e..3434047b12d3 100644
--- a/src/languages/en.ts
+++ b/src/languages/en.ts
@@ -3022,6 +3022,7 @@ const translations = {
         phoneOrEmail: 'Phone or email',
         error: {
             invalidFormatEmailLogin: 'The email entered is invalid. Please fix the format and try again.',
+            agentSignInBlocked: "Agent accounts can't be signed into directly. To use an agent, sign in with your own account and access it via Copilot.",
         },
         cannotGetAccountDetails: "Couldn't retrieve account details. Please try to sign in again.",
         loginForm: 'Login form',
diff --git a/src/languages/es.ts b/src/languages/es.ts
index f84ec9f6a162..a7ec746835ec 100644
--- a/src/languages/es.ts
+++ b/src/languages/es.ts
@@ -2831,6 +2831,8 @@ ${amount} para ${merchant} - ${date}`,
         phoneOrEmail: 'Número de teléfono o correo electrónico',
         error: {
             invalidFormatEmailLogin: 'El correo electrónico introducido no es válido. Corrígelo e inténtalo de nuevo.',
+            agentSignInBlocked:
+                'No se puede iniciar sesión directamente en las cuentas de agente. Para usar un agente, inicia sesión con tu propia cuenta y accede a él a través de Copilot.',
         },
         cannotGetAccountDetails: 'No se pudieron cargar los detalles de tu cuenta. Por favor, intenta iniciar sesión de nuevo.',
         loginForm: 'Formulario de inicio de sesión',
diff --git a/src/languages/fr.ts b/src/languages/fr.ts
index eb8b2d3b96f3..faea6c2a765e 100644
--- a/src/languages/fr.ts
+++ b/src/languages/fr.ts
@@ -2962,6 +2962,8 @@ ${amount} pour ${merchant} - ${date}`,
     loginForm: {
         phoneOrEmail: 'Téléphone ou e-mail',
         error: {
+            agentSignInBlocked:
+                'Les comptes d\u2019agent ne permettent pas de se connecter directement. Pour utiliser un agent, connectez-vous avec votre propre compte et accédez-y via Copilot.',
             invalidFormatEmailLogin: 'L’adresse e-mail saisie est invalide. Veuillez corriger le format et réessayer.',
         },
         cannotGetAccountDetails: 'Impossible de récupérer les détails du compte. Veuillez essayer de vous reconnecter.',
diff --git a/src/languages/it.ts b/src/languages/it.ts
index 8b55789d977a..3dc80464e652 100644
--- a/src/languages/it.ts
+++ b/src/languages/it.ts
@@ -2950,6 +2950,7 @@ ${amount} per ${merchant} - ${date}`,
     loginForm: {
         phoneOrEmail: 'Telefono o email',
         error: {
+            agentSignInBlocked: 'Non puoi accedere direttamente agli account agente. Per usare un agente, accedi con il tuo account e raggiungilo tramite Copilot.',
             invalidFormatEmailLogin: 'L’email inserita non è valida. Correggi il formato e riprova.',
         },
         cannotGetAccountDetails: 'Impossibile recuperare i dettagli dell’account. Prova ad accedere di nuovo.',
diff --git a/src/languages/ja.ts b/src/languages/ja.ts
index 7dadd52e6801..21f4138e59cd 100644
--- a/src/languages/ja.ts
+++ b/src/languages/ja.ts
@@ -2923,6 +2923,8 @@ ${date} の ${merchant} への ${amount}`,
         phoneOrEmail: '電話番号またはメールアドレス',
         error: {
             invalidFormatEmailLogin: '入力されたメールアドレスが無効です。形式を修正して、もう一度お試しください。',
+            agentSignInBlocked:
+                'エージェントアカウントには直接サインインすることはできません。エージェントを利用するには、ご自身のアカウントでサインインし、Copilot 経由でアクセスしてください。',
         },
         cannotGetAccountDetails: 'アカウントの詳細を取得できませんでした。もう一度サインインしてください。',
         loginForm: 'ログインフォーム',
diff --git a/src/languages/nl.ts b/src/languages/nl.ts
index 9a7bb8d0ffb0..60c19f6baa0e 100644
--- a/src/languages/nl.ts
+++ b/src/languages/nl.ts
@@ -2947,6 +2947,7 @@ ${amount} voor ${merchant} - ${date}`,
         phoneOrEmail: 'Telefoon of e-mail',
         error: {
             invalidFormatEmailLogin: 'Het ingevoerde e-mailadres is ongeldig. Corrigeer de notatie en probeer het opnieuw.',
+            agentSignInBlocked: 'Je kunt niet rechtstreeks inloggen op agent-accounts. Log in met je eigen account en gebruik de agent via Copilot.',
         },
         cannotGetAccountDetails: 'Accountgegevens konden niet worden opgehaald. Probeer opnieuw in te loggen.',
         loginForm: 'Aanmeldformulier',
diff --git a/src/languages/pl.ts b/src/languages/pl.ts
index f4011e201ee0..29bfc5e9248c 100644
--- a/src/languages/pl.ts
+++ b/src/languages/pl.ts
@@ -2941,6 +2941,7 @@ ${amount} dla ${merchant} - ${date}`,
         phoneOrEmail: 'Telefon lub e-mail',
         error: {
             invalidFormatEmailLogin: 'Wprowadzony adres e-mail jest nieprawidłowy. Popraw jego format i spróbuj ponownie.',
+            agentSignInBlocked: 'Na konta agenta nie można logować się bezpośrednio. Żeby korzystać z agenta, zaloguj się na własne konto i uzyskaj do niego dostęp przez Copilota.',
         },
         cannotGetAccountDetails: 'Nie można pobrać szczegółów konta. Spróbuj zalogować się ponownie.',
         loginForm: 'Formularz logowania',
diff --git a/src/languages/pt-BR.ts b/src/languages/pt-BR.ts
index da031573508b..df41fba7aa7a 100644
--- a/src/languages/pt-BR.ts
+++ b/src/languages/pt-BR.ts
@@ -2941,6 +2941,7 @@ ${amount} para ${merchant} - ${date}`,
         phoneOrEmail: 'Telefone ou e-mail',
         error: {
             invalidFormatEmailLogin: 'O e-mail inserido é inválido. Corrija o formato e tente novamente.',
+            agentSignInBlocked: 'Contas de agente não podem ser acessadas diretamente. Para usar um agente, entre com a sua própria conta e acesse-o via Copilot.',
         },
         cannotGetAccountDetails: 'Não foi possível recuperar os detalhes da conta. Tente entrar novamente.',
         loginForm: 'Formulário de login',
diff --git a/src/languages/zh-hans.ts b/src/languages/zh-hans.ts
index ea9c4e854831..b49ca205e666 100644
--- a/src/languages/zh-hans.ts
+++ b/src/languages/zh-hans.ts
@@ -2866,6 +2866,7 @@ ${amount}，商户：${merchant} - 日期：${date}`,
         phoneOrEmail: '电话或邮箱',
         error: {
             invalidFormatEmailLogin: '输入的邮箱无效。请修正格式后重试。',
+            agentSignInBlocked: '代理帐户无法直接登录。要使用代理，请先登录您自己的帐户，然后通过 Copilot 访问该代理。',
         },
         cannotGetAccountDetails: '无法获取账户详情。请尝试重新登录。',
         loginForm: '登录表单',
diff --git a/src/libs/SessionUtils.ts b/src/libs/SessionUtils.ts
index 250dfdbd74d5..0687784aaf0c 100644
--- a/src/libs/SessionUtils.ts
+++ b/src/libs/SessionUtils.ts
@@ -108,7 +108,7 @@ function checkIfShouldUseNewPartnerName(partnerUserID?: string): boolean {
     return false;
 }
 
-const AGENT_EMAIL_REGEX = /^agent_\d+@expensify\.ai$/;
+const AGENT_EMAIL_REGEX = /^agent_\d+@expensify\.ai$/i;
 
 function isAgentEmail(email?: string): boolean {
     if (!email) {
diff --git a/src/pages/signin/LoginForm/BaseLoginForm.tsx b/src/pages/signin/LoginForm/BaseLoginForm.tsx
index a156bd8ff94a..62437474629e 100644
--- a/src/pages/signin/LoginForm/BaseLoginForm.tsx
+++ b/src/pages/signin/LoginForm/BaseLoginForm.tsx
@@ -24,6 +24,7 @@ import {getLatestErrorMessage} from '@libs/ErrorUtils';
 import isInputAutoFilled from '@libs/isInputAutoFilled';
 import {appendCountryCode, getPhoneNumberWithoutSpecialChars} from '@libs/LoginUtils';
 import {parsePhoneNumber} from '@libs/PhoneNumber';
+import {isAgentEmail} from '@libs/SessionUtils';
 import StringUtils from '@libs/StringUtils';
 import {isNumericWithSpecialChars, isValidEmailWithTLD} from '@libs/ValidationUtils';
 import Visibility from '@libs/Visibility';
@@ -140,6 +141,12 @@ function BaseLoginForm({submitBehavior = 'submit', isVisible, ref}: BaseLoginFor
 
         const loginTrim = StringUtils.removeInvisibleCharacters(login.trim());
 
+        if (isAgentEmail(loginTrim)) {
+            setFormError('loginForm.error.agentSignInBlocked');
+            isLoading.current = false;
+            return;
+        }
+
         const phoneLogin = appendCountryCode(getPhoneNumberWithoutSpecialChars(loginTrim), countryCode);
         const parsedPhoneNumber = parsePhoneNumber(phoneLogin);
 
diff --git a/tests/ui/BaseLoginFormTest.tsx b/tests/ui/BaseLoginFormTest.tsx
new file mode 100644
index 000000000000..9b6070279043
--- /dev/null
+++ b/tests/ui/BaseLoginFormTest.tsx
@@ -0,0 +1,135 @@
+import type * as ReactNavigationNative from '@react-navigation/native';
+import {fireEvent, render, screen, waitFor} from '@testing-library/react-native';
+import React from 'react';
+import Onyx from 'react-native-onyx';
+import {LoginProvider} from '@pages/signin/SignInLoginContext';
+import {beginSignIn} from '@userActions/Session';
+import ONYXKEYS from '@src/ONYXKEYS';
+import waitForBatchedUpdates from '../utils/waitForBatchedUpdates';
+
+jest.mock('@react-navigation/native', () => {
+    const actualNav = jest.requireActual<typeof ReactNavigationNative>('@react-navigation/native');
+    return {
+        ...actualNav,
+        useIsFocused: () => true,
+    };
+});
+
+const AGENT_ERROR = "Agent accounts can't be signed into directly. To use an agent, sign in with your own account and access it via Copilot.";
+const INVALID_EMAIL_ERROR = 'The email entered is invalid. Please fix the format and try again.';
+
+jest.mock('@hooks/useLocalize', () =>
+    jest.fn(() => ({
+        translate: jest.fn((key: string) => {
+            switch (key) {
+                case 'loginForm.error.agentSignInBlocked':
+                    return AGENT_ERROR;
+                case 'loginForm.error.invalidFormatEmailLogin':
+                    return INVALID_EMAIL_ERROR;
+                case 'loginForm.phoneOrEmail':
+                    return 'Phone or email';
+                case 'loginForm.loginForm':
+                    return 'Login form';
+                case 'common.continue':
+                    return 'Continue';
+                case 'common.signInWith':
+                    return 'Sign in with';
+                case 'common.pleaseEnterEmailOrPhoneNumber':
+                    return 'Please enter an email or phone number';
+                default:
+                    return key;
+            }
+        }),
+        numberFormat: jest.fn(),
+    })),
+);
+
+jest.mock('@hooks/useResponsiveLayout', () =>
+    jest.fn(() => ({
+        shouldUseNarrowLayout: false,
+        isInNarrowPaneModal: false,
+    })),
+);
+
+jest.mock('@userActions/Session', () => ({
+    beginSignIn: jest.fn(),
+    clearAccountMessages: jest.fn(),
+    clearSignInData: jest.fn(),
+}));
+
+jest.mock('@userActions/CloseAccount', () => ({
+    setDefaultData: jest.fn(),
+}));
+
+// Use require to get the default export after all jest.mock calls are hoisted
+// eslint-disable-next-line @typescript-eslint/no-unsafe-assignment, @typescript-eslint/no-unsafe-member-access
+const BaseLoginForm = require('@pages/signin/LoginForm/BaseLoginForm').default;
+
+const mockBeginSignIn = beginSignIn as jest.MockedFunction<typeof beginSignIn>;
+
+function renderForm() {
+    return render(
+        <LoginProvider>
+            <BaseLoginForm isVisible />
+        </LoginProvider>,
+    );
+}
+
+describe('BaseLoginForm', () => {
+    beforeAll(() => {
+        Onyx.init({keys: ONYXKEYS});
+    });
+
+    beforeEach(async () => {
+        jest.clearAllMocks();
+        await Onyx.set(ONYXKEYS.ACCOUNT, {
+            isLoading: false,
+            errors: null,
+        });
+        await waitForBatchedUpdates();
+    });
+
+    it('shows agent sign-in blocked error when an agent email is entered', async () => {
+        renderForm();
+
+        const input = screen.getByTestId('username');
+        fireEvent.changeText(input, 'agent_123@expensify.ai');
+
+        const continueButton = screen.getByText('Continue');
+        fireEvent.press(continueButton);
+
+        await waitFor(() => {
+            expect(screen.getByText(AGENT_ERROR)).toBeTruthy();
+        });
+        expect(mockBeginSignIn).not.toHaveBeenCalled();
+    });
+
+    it('blocks agent email regardless of case', async () => {
+        renderForm();
+
+        const input = screen.getByTestId('username');
+        fireEvent.changeText(input, 'AGENT_123@EXPENSIFY.AI');
+
+        const continueButton = screen.getByText('Continue');
+        fireEvent.press(continueButton);
+
+        await waitFor(() => {
+            expect(screen.getByText(AGENT_ERROR)).toBeTruthy();
+        });
+        expect(mockBeginSignIn).not.toHaveBeenCalled();
+    });
+
+    it('proceeds with sign-in for a normal email', async () => {
+        renderForm();
+
+        const input = screen.getByTestId('username');
+        fireEvent.changeText(input, 'user@expensify.com');
+
+        const continueButton = screen.getByText('Continue');
+        fireEvent.press(continueButton);
+
+        await waitFor(() => {
+            expect(mockBeginSignIn).toHaveBeenCalledWith('user@expensify.com');
+        });
+    });
+});