diff --git a/.changeset/wise-mangos-push.md b/.changeset/wise-mangos-push.md
new file mode 100644
index 000000000..46ee03dbb
--- /dev/null
+++ b/.changeset/wise-mangos-push.md
@@ -0,0 +1,5 @@
+---
+"@near-js/biometric-ed25519": patch
+---
+
+Ensure passkey-derived keys are prefixed with ed25519
diff --git a/packages/biometric-ed25519/src/index.ts b/packages/biometric-ed25519/src/index.ts
index 28fff0c4d..d0f22dbd6 100644
--- a/packages/biometric-ed25519/src/index.ts
+++ b/packages/biometric-ed25519/src/index.ts
@@ -3,7 +3,7 @@ import { ed25519 } from '@noble/curves/ed25519';
 import { sha256 } from '@noble/hashes/sha256';
 import { Buffer } from 'buffer';
 import asn1 from 'asn1-parser';
-import { KeyPair } from '@near-js/crypto';
+import { KeyPair, KeyPairEd25519 } from '@near-js/crypto';
 import { baseEncode } from '@near-js/utils';
 import {
     validateUsername,
@@ -18,7 +18,6 @@ import {
 } from './utils';
 import { Fido2 } from './fido2';
 import type { AssertionResponse } from './type';
-import { KeyPairString } from '@near-js/crypto';
 
 const CHALLENGE_TIMEOUT_MS = 90 * 1000;
 const RP_NAME = 'NEAR_API_JS_WEBAUTHN';
@@ -87,7 +86,7 @@ export const createKey = async (username: string): Promise<KeyPair> => {
             const publicKeyBytes = get64BytePublicKeyFromPEM(publicKey);
             const secretKey = sha256.create().update(Buffer.from(publicKeyBytes)).digest();
             const pubKey = ed25519.getPublicKey(secretKey);
-            return KeyPair.fromString(baseEncode(new Uint8Array(Buffer.concat([Buffer.from(secretKey), Buffer.from(pubKey)]))) as KeyPairString);
+            return new KeyPairEd25519(baseEncode(Buffer.concat([Buffer.from(secretKey), Buffer.from(pubKey)])));
         });
 };
 
@@ -130,8 +129,8 @@ export const getKeys = async (username: string): Promise<[KeyPair, KeyPair]> =>
             const firstEDPublic = ed25519.getPublicKey(firstEDSecret);
             const secondEDSecret = sha256.create().update(Buffer.from(correctPKs[1])).digest();
             const secondEDPublic = ed25519.getPublicKey(secondEDSecret);
-            const firstKeyPair = KeyPair.fromString(baseEncode(new Uint8Array(Buffer.concat([Buffer.from(firstEDSecret), Buffer.from(firstEDPublic)]))) as KeyPairString);
-            const secondKeyPair = KeyPair.fromString(baseEncode(new Uint8Array(Buffer.concat([Buffer.from(secondEDSecret), Buffer.from(secondEDPublic)]))) as KeyPairString);
+            const firstKeyPair = new KeyPairEd25519(baseEncode(Buffer.concat([Buffer.from(firstEDSecret), Buffer.from(firstEDPublic)])));
+            const secondKeyPair = new KeyPairEd25519(baseEncode(Buffer.concat([Buffer.from(secondEDSecret), Buffer.from(secondEDPublic)])));
             return [firstKeyPair, secondKeyPair];
         });
 };