diff --git a/foundry.toml b/foundry.toml
index c873eaa4..2bc66fa7 100644
--- a/foundry.toml
+++ b/foundry.toml
@@ -4,8 +4,8 @@ fs_permissions = [{ access = "read-write", path = "./"}]
 [rpc_endpoints]
 # The RPC URLs are modified versions of the default for testing initialization.
 mainnet = "https://eth-mainnet.alchemyapi.io/v2/WV407BEiBmjNJfKo9Uo_55u0z0ITyCOX" # Different API key.
-optimism_goerli = "https://goerli.optimism.io/" # Adds a trailing slash.
-arbitrum_one_goerli = "https://goerli-rollup.arbitrum.io/rpc/" # Adds a trailing slash.
+optimism_sepolia = "https://sepolia.optimism.io/" # Adds a trailing slash.
+arbitrum_one_sepolia = "https://sepolia-rollup.arbitrum.io/rpc/" # Adds a trailing slash.
 needs_undefined_env_var = "${UNDEFINED_RPC_URL_PLACEHOLDER}"
 
 [fmt]
diff --git a/src/StdChains.sol b/src/StdChains.sol
index 27e1bf25..975f83bc 100644
--- a/src/StdChains.sol
+++ b/src/StdChains.sol
@@ -199,17 +199,17 @@ abstract contract StdChains {
         setChainWithDefaultRpcUrl(
             "mainnet", ChainData("Mainnet", 1, "https://eth-mainnet.alchemyapi.io/v2/pwc5rmJhrdoaSEfimoKEmsvOjKSmPDrP")
         );
-        setChainWithDefaultRpcUrl(
-            "goerli", ChainData("Goerli", 5, "https://goerli.infura.io/v3/b9794ad1ddf84dfb8c34d6bb5dca2001")
-        );
         setChainWithDefaultRpcUrl(
             "sepolia", ChainData("Sepolia", 11155111, "https://sepolia.infura.io/v3/b9794ad1ddf84dfb8c34d6bb5dca2001")
         );
+        setChainWithDefaultRpcUrl("holesky", ChainData("Holesky", 17000, "https://rpc.holesky.ethpandaops.io"));
         setChainWithDefaultRpcUrl("optimism", ChainData("Optimism", 10, "https://mainnet.optimism.io"));
-        setChainWithDefaultRpcUrl("optimism_goerli", ChainData("Optimism Goerli", 420, "https://goerli.optimism.io"));
+        setChainWithDefaultRpcUrl(
+            "optimism_sepolia", ChainData("Optimism Sepolia", 11155420, "https://sepolia.optimism.io")
+        );
         setChainWithDefaultRpcUrl("arbitrum_one", ChainData("Arbitrum One", 42161, "https://arb1.arbitrum.io/rpc"));
         setChainWithDefaultRpcUrl(
-            "arbitrum_one_goerli", ChainData("Arbitrum One Goerli", 421613, "https://goerli-rollup.arbitrum.io/rpc")
+            "arbitrum_one_sepolia", ChainData("Arbitrum One Sepolia", 421614, "https://sepolia-rollup.arbitrum.io/rpc")
         );
         setChainWithDefaultRpcUrl("arbitrum_nova", ChainData("Arbitrum Nova", 42170, "https://nova.arbitrum.io/rpc"));
         setChainWithDefaultRpcUrl("polygon", ChainData("Polygon", 137, "https://polygon-rpc.com"));
@@ -233,7 +233,7 @@ abstract contract StdChains {
             "moonriver", ChainData("Moonriver", 1285, "https://rpc.api.moonriver.moonbeam.network")
         );
         setChainWithDefaultRpcUrl("moonbase", ChainData("Moonbase", 1287, "https://rpc.testnet.moonbeam.network"));
-        setChainWithDefaultRpcUrl("base_goerli", ChainData("Base Goerli", 84531, "https://goerli.base.org"));
+        setChainWithDefaultRpcUrl("base_sepolia", ChainData("Base Sepolia", 84532, "https://sepolia.base.org"));
         setChainWithDefaultRpcUrl("base", ChainData("Base", 8453, "https://mainnet.base.org"));
         setChainWithDefaultRpcUrl("fraxtal", ChainData("Fraxtal", 252, "https://rpc.frax.com"));
         setChainWithDefaultRpcUrl("fraxtal_testnet", ChainData("Fraxtal Testnet", 2522, "https://rpc.testnet.frax.com"));
diff --git a/test/StdChains.t.sol b/test/StdChains.t.sol
index 4c3283a7..957e5b05 100644
--- a/test/StdChains.t.sol
+++ b/test/StdChains.t.sol
@@ -25,8 +25,8 @@ contract StdChainsTest is Test {
     function test_ChainRpcInitialization() public {
         // RPCs specified in `foundry.toml` should be updated.
         assertEq(getChain(1).rpcUrl, "https://eth-mainnet.alchemyapi.io/v2/WV407BEiBmjNJfKo9Uo_55u0z0ITyCOX");
-        assertEq(getChain("optimism_goerli").rpcUrl, "https://goerli.optimism.io/");
-        assertEq(getChain("arbitrum_one_goerli").rpcUrl, "https://goerli-rollup.arbitrum.io/rpc/");
+        assertEq(getChain("optimism_sepolia").rpcUrl, "https://sepolia.optimism.io/");
+        assertEq(getChain("arbitrum_one_sepolia").rpcUrl, "https://sepolia-rollup.arbitrum.io/rpc/");
 
         // Environment variables should be the next fallback
         assertEq(getChain("arbitrum_nova").rpcUrl, "https://nova.arbitrum.io/rpc");
@@ -54,12 +54,12 @@ contract StdChainsTest is Test {
     // Currently commented out since this is slow and public RPCs are flaky, often resulting in failing CI.
     // function test_Rpcs() public {
     //     _testRpc("mainnet");
-    //     _testRpc("goerli");
     //     _testRpc("sepolia");
+    //     _testRpc("holesky");
     //     _testRpc("optimism");
-    //     _testRpc("optimism_goerli");
+    //     _testRpc("optimism_sepolia");
     //     _testRpc("arbitrum_one");
-    //     _testRpc("arbitrum_one_goerli");
+    //     _testRpc("arbitrum_one_sepolia");
     //     _testRpc("arbitrum_nova");
     //     _testRpc("polygon");
     //     _testRpc("polygon_mumbai");
@@ -71,7 +71,7 @@ contract StdChainsTest is Test {
     //     _testRpc("moonbeam");
     //     _testRpc("moonriver");
     //     _testRpc("moonbase");
-    //     _testRpc("base_goerli");
+    //     _testRpc("base_sepolia");
     //     _testRpc("base");
     //     _testRpc("fraxtal");
     //     _testRpc("fraxtal_testnet");
diff --git a/test/StdCheats.t.sol b/test/StdCheats.t.sol
index e96cb52d..7bac4286 100644
--- a/test/StdCheats.t.sol
+++ b/test/StdCheats.t.sol
@@ -400,7 +400,7 @@ contract StdCheatsTest is Test {
     }
 
     function testFuzz_AssumeNotPrecompile(address addr) external {
-        assumeNotPrecompile(addr, getChain("optimism_goerli").chainId);
+        assumeNotPrecompile(addr, getChain("optimism_sepolia").chainId);
         assertTrue(
             addr < address(1) || (addr > address(9) && addr < address(0x4200000000000000000000000000000000000000))
                 || addr > address(0x4200000000000000000000000000000000000800)