diff --git a/src/index.ts b/src/index.ts
index 8b0d58fe..1bdda2d8 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -552,7 +552,7 @@ export class Multiaddr {
   /**
    * Check if object is a CID instance
    */
-  static isMultiaddr (value: any) {
+  static isMultiaddr (value: any): value is Multiaddr {
     return value instanceof Multiaddr ?? Boolean(value?.[symbol])
   }