diff --git a/system/Config/Services.php b/system/Config/Services.php
index c0d5fcc392d2..3ec00110e694 100644
--- a/system/Config/Services.php
+++ b/system/Config/Services.php
@@ -197,6 +197,7 @@ public static function csp(?CSPConfig $config = null, bool $getShared = true)
     /**
      * The CURL Request class acts as a simple HTTP client for interacting
      * with other servers, typically through APIs.
+     * The option 'base_uri' is deprecated and will be remove soon.
      *
      * @return CURLRequest
      */
@@ -208,10 +209,12 @@ public static function curlrequest(array $options = [], ?ResponseInterface $resp
 
         $config ??= config(App::class);
         $response ??= new Response($config);
+        $uri = new URI($options['baseURI'] ?? $options['base_uri'] ?? null);
+        unset($options['baseURI']);
 
         return new CURLRequest(
             $config,
-            new URI($options['base_uri'] ?? null),
+            $uri,
             $response,
             $options
         );
diff --git a/system/HTTP/CURLRequest.php b/system/HTTP/CURLRequest.php
index 9da231c17716..956c293b8761 100644
--- a/system/HTTP/CURLRequest.php
+++ b/system/HTTP/CURLRequest.php
@@ -39,13 +39,6 @@ class CURLRequest extends OutgoingRequest
      */
     protected $responseOrig;
 
-    /**
-     * The URI associated with this request
-     *
-     * @var URI
-     */
-    protected $baseURI;
-
     /**
      * The setting values
      *
@@ -104,7 +97,6 @@ class CURLRequest extends OutgoingRequest
     /**
      * Takes an array of options to set the following possible class properties:
      *
-     *  - baseURI
      *  - timeout
      *  - any other request options to use as defaults.
      *
@@ -116,13 +108,13 @@ public function __construct(App $config, URI $uri, ?ResponseInterface $response
             throw HTTPException::forMissingCurl(); // @codeCoverageIgnore
         }
 
+        $uri->useRawQueryString();
         parent::__construct(Method::GET, $uri);
 
         $this->responseOrig = $response ?? new Response($config);
         // Remove the default Content-Type header.
         $this->responseOrig->removeHeader('Content-Type');
 
-        $this->baseURI        = $uri->useRawQueryString();
         $this->defaultOptions = $options;
 
         /** @var ConfigCURLRequest|null $configCURLRequest */
@@ -135,7 +127,7 @@ public function __construct(App $config, URI $uri, ?ResponseInterface $response
 
     /**
      * Sends an HTTP request to the specified $url. If this is a relative
-     * URL, it will be merged with $this->baseURI to form a complete URL.
+     * URL, it will be merged with $options['baseURI'] or $this->uri to form a complete URL.
      *
      * @param string $method HTTP method
      */
@@ -143,9 +135,16 @@ public function request($method, string $url, array $options = []): ResponseInte
     {
         $this->response = clone $this->responseOrig;
 
+        if (array_key_exists('baseURI', $options)) {
+            $uri = new URI($options['baseURI']);
+            $uri->useRawQueryString();
+            unset($options['baseURI']);
+        } else {
+            $uri = $this->uri;
+        }
         $this->parseOptions($options);
 
-        $url = $this->prepareURL($url);
+        $url = $this->prepareURL($url, $uri);
 
         $method = esc(strip_tags($method));
 
@@ -293,11 +292,6 @@ public function setJSON($data)
      */
     protected function parseOptions(array $options)
     {
-        if (array_key_exists('baseURI', $options)) {
-            $this->baseURI = $this->baseURI->setURI($options['baseURI']);
-            unset($options['baseURI']);
-        }
-
         if (array_key_exists('headers', $options) && is_array($options['headers'])) {
             foreach ($options['headers'] as $name => $value) {
                 $this->setHeader($name, $value);
@@ -325,16 +319,16 @@ protected function parseOptions(array $options)
 
     /**
      * If the $url is a relative URL, will attempt to create
-     * a full URL by prepending $this->baseURI to it.
+     * a full URL by prepending $uri to it.
      */
-    protected function prepareURL(string $url): string
+    protected function prepareURL(string $url, URI $uri): string
     {
         // If it's a full URI, then we have nothing to do here...
         if (str_contains($url, '://')) {
             return $url;
         }
 
-        $uri = $this->baseURI->resolveRelativeURI($url);
+        $uri = $uri->resolveRelativeURI($url);
 
         // Create the string instead of casting to prevent baseURL muddling
         return URI::createURIString(
diff --git a/system/Test/Mock/MockCURLRequest.php b/system/Test/Mock/MockCURLRequest.php
index 97f80e7c1da2..1c0c8b0af03a 100644
--- a/system/Test/Mock/MockCURLRequest.php
+++ b/system/Test/Mock/MockCURLRequest.php
@@ -44,12 +44,6 @@ protected function sendRequest(array $curlOptions = []): string
         return $this->output;
     }
 
-    // for testing purposes only
-    public function getBaseURI()
-    {
-        return $this->baseURI;
-    }
-
     // for testing purposes only
     public function getDelay()
     {