diff --git a/src/utils.ts b/src/utils.ts
index 3f324936..2fd9c25e 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -8,7 +8,7 @@ export function isRelative (inputStr: string) {
 }
 
 export function hasProtocol (inputStr: string, acceptProtocolRelative = false): boolean {
-  return /^\w+:\/\/.+/.test(inputStr) || (acceptProtocolRelative && /^\/\/[^/]+/.test(inputStr))
+  return /^\w+:(\/\/)?.+/.test(inputStr) || (acceptProtocolRelative && /^\/\/[^/]+/.test(inputStr))
 }
 
 const TRAILING_SLASH_RE = /\/$|\/\?/
diff --git a/test/utilities.test.ts b/test/utilities.test.ts
index f4714a97..e1f5f4d3 100644
--- a/test/utilities.test.ts
+++ b/test/utilities.test.ts
@@ -6,10 +6,13 @@ describe('hasProtocol', () => {
     { input: '//', out: [false, false] },
     { input: '///', out: [false, false] },
     { input: '//test.com', out: [true, false] },
-    { input: 'https://', out: [false, false] },
+    { input: 'https://', out: [true, true] },
     { input: 'https://test.com', out: [true, true] },
     { input: '/test', out: [false, false] },
-    { input: 'file:///home/user', out: [true, true] }
+    { input: 'file:///home/user', out: [true, true] },
+    { input: 'tel:', out: [false, false] },
+    { input: 'tel:123456', out: [true, true] },
+    { input: 'mailto:support@example.com', out: [true, true] }
   ]
 
   for (const t of tests) {