diff --git a/packages/ui/src/apis/register.ts b/packages/ui/src/apis/register.ts
index b664e32b1..f749ada42 100644
--- a/packages/ui/src/apis/register.ts
+++ b/packages/ui/src/apis/register.ts
@@ -73,10 +73,9 @@ export const verifyRegisterEmailPasscode = async (email: string, code: string) =
     })
     .json<Response>();
 
-// TODO: @simeng LOG-4503
-export const verifyUsernameExistence = async (username: string) => {
+export const checkUsername = async (username: string) => {
   await api
-    .post(`${apiPrefix}/check/username`, {
+    .post(`${apiPrefix}/register/password/check-username`, {
       json: {
         username,
       },
diff --git a/packages/ui/src/containers/UsernameRegister/index.test.tsx b/packages/ui/src/containers/UsernameRegister/index.test.tsx
index 590c40556..8587e4cc0 100644
--- a/packages/ui/src/containers/UsernameRegister/index.test.tsx
+++ b/packages/ui/src/containers/UsernameRegister/index.test.tsx
@@ -2,7 +2,7 @@ import { fireEvent, act, waitFor } from '@testing-library/react';
 
 import renderWithPageContext from '@/__mocks__/RenderWithPageContext';
 import SettingsProvider from '@/__mocks__/RenderWithPageContext/SettingsProvider';
-import { verifyUsernameExistence } from '@/apis/register';
+import { checkUsername } from '@/apis/register';
 
 import UsernameRegister from '.';
 
@@ -14,7 +14,7 @@ jest.mock('react-router-dom', () => ({
 }));
 
 jest.mock('@/apis/register', () => ({
-  verifyUsernameExistence: jest.fn(async () => ({})),
+  checkUsername: jest.fn(async () => ({})),
 }));
 
 describe('<UsernameRegister />', () => {
@@ -40,7 +40,7 @@ describe('<UsernameRegister />', () => {
 
     expect(queryByText('username_required')).not.toBeNull();
 
-    expect(verifyUsernameExistence).not.toBeCalled();
+    expect(checkUsername).not.toBeCalled();
   });
 
   test('username with initial numeric char should throw', () => {
@@ -57,7 +57,7 @@ describe('<UsernameRegister />', () => {
 
     expect(queryByText('username_should_not_start_with_number')).not.toBeNull();
 
-    expect(verifyUsernameExistence).not.toBeCalled();
+    expect(checkUsername).not.toBeCalled();
 
     // Clear error
     if (usernameInput) {
@@ -80,7 +80,7 @@ describe('<UsernameRegister />', () => {
 
     expect(queryByText('username_valid_charset')).not.toBeNull();
 
-    expect(verifyUsernameExistence).not.toBeCalled();
+    expect(checkUsername).not.toBeCalled();
 
     // Clear error
     if (usernameInput) {
@@ -111,7 +111,7 @@ describe('<UsernameRegister />', () => {
     });
 
     await waitFor(() => {
-      expect(verifyUsernameExistence).toBeCalledWith('username');
+      expect(checkUsername).toBeCalledWith('username');
     });
   });
 });
diff --git a/packages/ui/src/containers/UsernameRegister/index.tsx b/packages/ui/src/containers/UsernameRegister/index.tsx
index 904c40472..7dda69431 100644
--- a/packages/ui/src/containers/UsernameRegister/index.tsx
+++ b/packages/ui/src/containers/UsernameRegister/index.tsx
@@ -4,7 +4,7 @@ import { useCallback, useMemo } from 'react';
 import { useTranslation } from 'react-i18next';
 import { useNavigate } from 'react-router-dom';
 
-import { verifyUsernameExistence } from '@/apis/register';
+import { checkUsername } from '@/apis/register';
 import Button from '@/components/Button';
 import Input from '@/components/Input';
 import TermsOfUse from '@/containers/TermsOfUse';
@@ -54,7 +54,7 @@ const UsernameRegister = ({ className }: Props) => {
     [setFieldErrors]
   );
 
-  const { run: asyncVerifyUsername } = useApi(verifyUsernameExistence, errorHandlers);
+  const { run: asyncCheckUsername } = useApi(checkUsername, errorHandlers);
 
   const onSubmitHandler = useCallback(
     async (event?: React.FormEvent<HTMLFormElement>) => {
@@ -71,7 +71,7 @@ const UsernameRegister = ({ className }: Props) => {
       const { username } = fieldValue;
 
       // Use sync call for this api to make sure the username value being passed to the password set page stays the same
-      const result = await asyncVerifyUsername(username);
+      const result = await asyncCheckUsername(username);
 
       if (result) {
         navigate(`/${UserFlow.register}/${SignInIdentifier.Username}/password`, {
@@ -79,7 +79,7 @@ const UsernameRegister = ({ className }: Props) => {
         });
       }
     },
-    [validateForm, termsValidation, fieldValue, asyncVerifyUsername, navigate]
+    [validateForm, termsValidation, fieldValue, asyncCheckUsername, navigate]
   );
 
   return (