diff --git a/lib/plugin.js b/lib/plugin.js
index 614333d..e47325d 100644
--- a/lib/plugin.js
+++ b/lib/plugin.js
@@ -82,7 +82,10 @@ for (let method of ['get', 'head', 'delete', 'post', 'put', 'patch']) {
 
     if (/^https?/.test(url)) {
       delete _options.prefixUrl
-    }
+    } else if (_options.prefixUrl && typeof url === 'string' && url.startsWith('/')) {
+      // Prevents `ky` from throwing "`input` must not begin with a slash when using `prefixUrl`"
+      url = url.substr(1)
+    } 
 
     try {
       const response = await this._ky[method](url, _options)