diff --git a/packages/networks/src.ts/index.ts b/packages/networks/src.ts/index.ts
index 998e3f8eb..c223030a3 100644
--- a/packages/networks/src.ts/index.ts
+++ b/packages/networks/src.ts/index.ts
@@ -183,10 +183,18 @@ const networks: { [name: string]: Network } = {
 
     xdai: { chainId: 100, name: "xdai" },
 
-    matic: { chainId: 137, name: "matic" },
+    matic: {
+        chainId: 137,
+        name: "matic",
+        _defaultProvider: ethDefaultProvider("matic")
+    },
     maticmum: { chainId: 80001, name: "maticmum" },
 
-    optimism: { chainId: 10, name: "optimism" },
+    optimism: {
+        chainId: 10,
+        name: "optimism",
+        _defaultProvider: ethDefaultProvider("optimism")
+    },
     "optimism-kovan": { chainId: 69, name: "optimism-kovan" },
     "optimism-goerli": { chainId: 420, name: "optimism-goerli" },