diff --git a/modules/sdk-coin-tao/src/lib/utils.ts b/modules/sdk-coin-tao/src/lib/utils.ts
index 1f85d04953..8a0b702a19 100644
--- a/modules/sdk-coin-tao/src/lib/utils.ts
+++ b/modules/sdk-coin-tao/src/lib/utils.ts
@@ -8,8 +8,10 @@ export class Utils extends SubstrateUtils {
     return (networkType === NetworkType.MAINNET ? mainnetMaterial : testnetMaterial) as unknown as Interface.Material;
   }
 
-  getTaoTokenBySubnetId(subnetId: string): Readonly<CoinConfig> {
-    const tokens = coins.filter((coin) => coin instanceof TaoCoin && coin.subnetId === subnetId).map((coin) => coin);
+  getTaoTokenBySubnetId(subnetId: string | number): Readonly<CoinConfig> {
+    const tokens = coins
+      .filter((coin) => coin instanceof TaoCoin && coin.subnetId === String(subnetId))
+      .map((coin) => coin);
 
     assert(tokens.length > 0, `No Tao token found for subnetId: ${subnetId}`);
     assert(tokens.length === 1, `Multiple Tao tokens found for subnetId: ${subnetId}`);
diff --git a/modules/sdk-coin-tao/test/unit/util.ts b/modules/sdk-coin-tao/test/unit/util.ts
new file mode 100644
index 0000000000..2a3329c4ad
--- /dev/null
+++ b/modules/sdk-coin-tao/test/unit/util.ts
@@ -0,0 +1,24 @@
+import utils from '../../src/lib/utils';
+
+describe('Tao utils', function () {
+  describe('getTaoTokenBySubnetId', function () {
+    it('should succeed for valid string subnetId', function () {
+      const token = utils.getTaoTokenBySubnetId('1');
+      token.name.should.equal('ttao:apex');
+    });
+    it('should succeed for valid number subnetId', function () {
+      const token = utils.getTaoTokenBySubnetId(1);
+      token.name.should.equal('ttao:apex');
+    });
+    it('should fail for invalid subnetId', function () {
+      (() => utils.getTaoTokenBySubnetId('invalid')).should.throw('No Tao token found for subnetId: invalid');
+    });
+    it('should fail for non-existent subnetId', function () {
+      (() => utils.getTaoTokenBySubnetId(999)).should.throw('No Tao token found for subnetId: 999');
+    });
+    it('should fail for undefined subnetId', function () {
+      // @ts-expect-error testing failure case
+      (() => utils.getTaoTokenBySubnetId(undefined)).should.throw('No Tao token found for subnetId: undefined');
+    });
+  });
+});