diff --git a/api/authentication/apis.py b/api/authentication/apis.py
new file mode 100644
index 0000000..455ddec
--- /dev/null
+++ b/api/authentication/apis.py
@@ -0,0 +1,22 @@
+from rest_framework import permissions, serializers, status
+from rest_framework.response import Response
+from rest_framework.views import APIView
+
+from api.authentication.selectors import validate_phone
+from api.common.validators import is_phone
+
+
+class ValidatePhoneAPI(APIView):
+    permission_classes = [permissions.AllowAny]
+
+    class InputSerializer(serializers.Serializer):
+        phone = serializers.CharField(validators=[is_phone])
+
+    def post(self, request):
+        serializer = self.InputSerializer(data=request.data)
+        serializer.is_valid(raise_exception=True)
+
+        # Raises validation error if phone is taken
+        validate_phone(**serializer.validated_data)
+
+        return Response(status=status.HTTP_200_OK)
diff --git a/api/authentication/selectors.py b/api/authentication/selectors.py
new file mode 100644
index 0000000..aeeffcc
--- /dev/null
+++ b/api/authentication/selectors.py
@@ -0,0 +1,12 @@
+from typing import Union
+
+from rest_framework.exceptions import ValidationError
+
+from api.users.models import User
+
+
+def validate_phone(*, phone: str) -> Union[None, ValidationError]:
+    if User.objects.filter(username=phone).exists():
+        raise ValidationError(f"Phone number: {phone} already taken")
+
+    return None
diff --git a/api/authentication/tests.py b/api/authentication/tests.py
deleted file mode 100644
index 007eb95..0000000
--- a/api/authentication/tests.py
+++ /dev/null
@@ -1 +0,0 @@
-# Tests
diff --git a/api/authentication/urls.py b/api/authentication/urls.py
index 78ccf87..e0005a9 100644
--- a/api/authentication/urls.py
+++ b/api/authentication/urls.py
@@ -5,9 +5,12 @@
     TokenVerifyView,
 )
 
+from api.authentication.apis import ValidatePhoneAPI
+
 app_name = "auth"
 urlpatterns = [
     path("token/", TokenObtainPairView.as_view(), name="obtain_token"),
     path("token/refresh/", TokenRefreshView.as_view(), name="refresh_token"),
     path("token/verify/", TokenVerifyView.as_view(), name="verify_token"),
+    path("phone/validate/", ValidatePhoneAPI.as_view(), name="validate_phone"),
 ]
diff --git a/api/authentication/views.py b/api/authentication/views.py
deleted file mode 100644
index 5873694..0000000
--- a/api/authentication/views.py
+++ /dev/null
@@ -1 +0,0 @@
-# Views
diff --git a/api/users/validators.py b/api/common/validators.py
similarity index 100%
rename from api/users/validators.py
rename to api/common/validators.py
diff --git a/api/users/migrations/0001_initial.py b/api/users/migrations/0001_initial.py
index 03e3c3a..16fd85c 100644
--- a/api/users/migrations/0001_initial.py
+++ b/api/users/migrations/0001_initial.py
@@ -1,6 +1,6 @@
 # Generated by Django 3.2.13 on 2022-04-19 22:39
 
-import api.users.validators
+import api.common.validators
 import django.contrib.auth.models
 from django.db import migrations, models
 import django.db.models.deletion
@@ -29,7 +29,7 @@ class Migration(migrations.Migration):
                 ('date_joined', models.DateTimeField(default=django.utils.timezone.now, verbose_name='date joined')),
                 ('name', models.CharField(max_length=256)),
                 ('email', models.EmailField(blank=True, max_length=254, null=True)),
-                ('username', models.CharField(max_length=10, unique=True, validators=[api.users.validators.is_phone])),
+                ('username', models.CharField(max_length=10, unique=True, validators=[api.common.validators.is_phone])),
                 ('id_exp_date', models.DateTimeField(blank=True, null=True)),
                 ('id_photo_url', models.ImageField(blank=True, upload_to='id-photos/')),
                 ('firebase_token', models.CharField(blank=True, max_length=256, unique=True)),
diff --git a/api/users/models.py b/api/users/models.py
index b906a50..ddccd3f 100644
--- a/api/users/models.py
+++ b/api/users/models.py
@@ -3,8 +3,8 @@
 from django.urls import reverse
 from django.utils import timezone
 
+from api.common.validators import is_phone
 from api.locations.models import Location
-from api.users.validators import is_phone
 
 
 class User(AbstractUser):