diff --git a/packages/core/src/constants/chainId.ts b/packages/core/src/constants/chainId.ts
index 8f02f9838..fd040f201 100644
--- a/packages/core/src/constants/chainId.ts
+++ b/packages/core/src/constants/chainId.ts
@@ -46,6 +46,7 @@ import {
   ThetaTestnet,
   ThunderCore,
   ThunderCoreTestnet,
+  OptimismSepolia,
   OptimismGoerli,
   OptimismKovan,
   Optimism,
@@ -119,6 +120,7 @@ export const DEFAULT_SUPPORTED_CHAINS = [
   ThetaTestnet,
   ThunderCore,
   ThunderCoreTestnet,
+  OptimismSepolia,
   OptimismGoerli,
   OptimismKovan,
   Optimism,
@@ -185,6 +187,7 @@ export enum ChainId {
   OasisEmeraldTestnet = 42261,
   Stardust = 588,
   Andromeda = 1088,
+  OptimismSepolia = 11155420,
   OptimismGoerli = 420,
   OptimismKovan = 69,
   Optimism = 10,