diff --git a/pyproject.toml b/pyproject.toml
index 8a13280e..f1baeabe 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -82,7 +82,7 @@ optional-dependencies.dev = [
     "ty==0.0.17",
     "types-requests==2.32.4.20260107",
     "vulture==2.14",
-    "vws-python-mock==2026.2.21",
+    "vws-python-mock==2026.2.22.2",
     "vws-test-fixtures==2023.3.5",
     "yamlfix==1.19.1",
     "zizmor==1.22.0",
diff --git a/src/vws/_vws_request.py b/src/vws/_vws_request.py
index 0ea91438..2fc7bd3b 100644
--- a/src/vws/_vws_request.py
+++ b/src/vws/_vws_request.py
@@ -2,8 +2,6 @@
 API.
 """
 
-from urllib.parse import urljoin
-
 import requests
 from beartype import BeartypeConf, beartype
 from vws_auth_tools import authorization_header, rfc_1123_date
@@ -64,7 +62,7 @@ def target_api_request(
         **extra_headers,
     }
 
-    url = urljoin(base=base_vws_url, url=request_path)
+    url = base_vws_url.rstrip("/") + request_path
 
     requests_response = requests.request(
         method=method,
diff --git a/src/vws/query.py b/src/vws/query.py
index 9c997177..f5046bd1 100644
--- a/src/vws/query.py
+++ b/src/vws/query.py
@@ -5,7 +5,6 @@
 import json
 from http import HTTPMethod, HTTPStatus
 from typing import Any, BinaryIO
-from urllib.parse import urljoin
 
 import requests
 from beartype import BeartypeConf, beartype
@@ -146,7 +145,7 @@ def query(
 
         requests_response = requests.request(
             method=method,
-            url=urljoin(base=self._base_vwq_url, url=request_path),
+            url=self._base_vwq_url.rstrip("/") + request_path,
             headers=headers,
             data=content,
             timeout=self._request_timeout_seconds,
diff --git a/tests/test_query.py b/tests/test_query.py
index b7f9687d..66d59611 100644
--- a/tests/test_query.py
+++ b/tests/test_query.py
@@ -190,6 +190,39 @@ def test_custom_base_url(image: io.BytesIO | BinaryIO) -> None:
             match = matches[0]
             assert match.target_id == target_id
 
+    @staticmethod
+    def test_custom_base_url_with_path_prefix(
+        image: io.BytesIO | BinaryIO,
+    ) -> None:
+        """
+        A base VWQ URL with a path prefix is used as-is, without the
+        prefix being dropped.
+        """
+        base_vwq_url = "http://example.com/prefix"
+        with MockVWS(base_vwq_url=base_vwq_url) as mock:
+            database = CloudDatabase()
+            mock.add_cloud_database(cloud_database=database)
+            vws_client = VWS(
+                server_access_key=database.server_access_key,
+                server_secret_key=database.server_secret_key,
+            )
+            target_id = vws_client.add_target(
+                name="x",
+                width=1,
+                image=image,
+                active_flag=True,
+                application_metadata=None,
+            )
+            vws_client.wait_for_target_processed(target_id=target_id)
+            cloud_reco_client = CloudRecoService(
+                client_access_key=database.client_access_key,
+                client_secret_key=database.client_secret_key,
+                base_vwq_url=base_vwq_url,
+            )
+
+            matches = cloud_reco_client.query(image=image)
+            assert len(matches) == 1
+
 
 class TestMaxNumResults:
     """Tests for the ``max_num_results`` parameter of ``query``."""
diff --git a/tests/test_vws.py b/tests/test_vws.py
index 0b435503..29bd3aa3 100644
--- a/tests/test_vws.py
+++ b/tests/test_vws.py
@@ -246,6 +246,24 @@ def test_custom_base_url(image: io.BytesIO | BinaryIO) -> None:
                 application_metadata=None,
             )
 
+    @staticmethod
+    def test_custom_base_url_with_path_prefix() -> None:
+        """
+        A base VWS URL with a path prefix is used as-is, without the
+        prefix being dropped.
+        """
+        base_vws_url = "http://example.com/prefix"
+        with MockVWS(base_vws_url=base_vws_url) as mock:
+            database = CloudDatabase()
+            mock.add_cloud_database(cloud_database=database)
+            vws_client = VWS(
+                server_access_key=database.server_access_key,
+                server_secret_key=database.server_secret_key,
+                base_vws_url=base_vws_url,
+            )
+
+            assert not vws_client.list_targets()
+
 
 class TestListTargets:
     """Tests for listing targets."""