diff --git a/package.json b/package.json
index 6dcf11a1d..56e6329a3 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "opensea-js",
-  "version": "6.1.5",
+  "version": "6.1.6",
   "description": "JavaScript SDK for the OpenSea marketplace helps developers build new experiences using NFTs and our marketplace data!",
   "license": "MIT",
   "author": "OpenSea Developers",
diff --git a/src/types.ts b/src/types.ts
index 36333ff55..ee3573fae 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -106,6 +106,8 @@ export enum Chain {
   Polygon = "matic",
   /** Klaytn */
   Klaytn = "klaytn",
+  /** Base L2 */
+  Base = "base",
   /** Binance Smart Chain */
   BNB = "bsc",
   /** Arbitrum */
@@ -122,6 +124,7 @@ export enum Chain {
   Zora = "zora",
 
   // Testnet Chains
+  // ⚠️NOTE: When adding to this list, also add to the util function `isTestChain`
   /** Goerli */
   Goerli = "goerli",
   /** Sepolia */
@@ -130,6 +133,8 @@ export enum Chain {
   Mumbai = "mumbai",
   /** Klaytn Baobab */
   Baobab = "baobab",
+  /** Base L2 Testnet */
+  BaseGoerli = "base_goerli",
   /** Binance Smart Chain Testnet */
   BNBTestnet = "bsctestnet",
   /** Arbitrum Testnet */
diff --git a/src/utils/utils.ts b/src/utils/utils.ts
index a6322703a..7c99df73b 100644
--- a/src/utils/utils.ts
+++ b/src/utils/utils.ts
@@ -344,7 +344,10 @@ export const getWETHAddress = (chain: Chain) => {
     case Chain.BNBTestnet:
       return "0xae13d989dac2f0debff460ac112a837c89baa7cd";
     // OP Chains have weth at the same address
+    case Chain.Base:
+    case Chain.BaseGoerli:
     case Chain.Optimism:
+    case Chain.OptimismGoerli:
     case Chain.Zora:
     case Chain.ZoraTestnet:
       return "0x4200000000000000000000000000000000000006";
@@ -397,6 +400,7 @@ export const isTestChain = (chain: Chain): boolean => {
     case Chain.Sepolia:
     case Chain.Mumbai:
     case Chain.Baobab:
+    case Chain.BaseGoerli:
     case Chain.BNBTestnet:
     case Chain.ArbitrumGoerli:
     case Chain.Fuji: