diff --git a/.changeset/soft-boxes-reply.md b/.changeset/soft-boxes-reply.md
new file mode 100644
index 0000000000..14fca24a6f
--- /dev/null
+++ b/.changeset/soft-boxes-reply.md
@@ -0,0 +1,6 @@
+---
+"viem": patch
+---
+
+Added Garnet chain.
+Updated Redstone chain.
diff --git a/src/chains/definitions/garnet.ts b/src/chains/definitions/garnet.ts
new file mode 100644
index 0000000000..e5ddd75301
--- /dev/null
+++ b/src/chains/definitions/garnet.ts
@@ -0,0 +1,49 @@
+import { chainConfig } from '../../op-stack/chainConfig.js'
+import { defineChain } from '../../utils/chain/defineChain.js'
+
+const sourceId = 17000 // Holesky testnet
+
+export const garnet = defineChain({
+  ...chainConfig,
+  name: 'Garnet Testnet',
+  testnet: true,
+  id: 17069,
+  sourceId,
+  nativeCurrency: { name: 'Ether', symbol: 'ETH', decimals: 18 },
+  rpcUrls: {
+    default: {
+      http: ['https://rpc.garnetchain.com'],
+      webSocket: ['wss://rpc.garnetchain.com'],
+    },
+  },
+  blockExplorers: {
+    default: {
+      name: 'Blockscout',
+      url: 'https://explorer.garnetchain.com',
+    },
+  },
+  contracts: {
+    ...chainConfig.contracts,
+    multicall3: {
+      address: '0xca11bde05977b3631167028862be2a173976ca11',
+    },
+    portal: {
+      [sourceId]: {
+        address: '0x57ee40586fbE286AfC75E67cb69511A6D9aF5909',
+        blockCreated: 1274684,
+      },
+    },
+    l2OutputOracle: {
+      [sourceId]: {
+        address: '0xCb8E7AC561b8EF04F2a15865e9fbc0766FEF569B',
+        blockCreated: 1274684,
+      },
+    },
+    l1StandardBridge: {
+      [sourceId]: {
+        address: '0x09bcDd311FE398F80a78BE37E489f5D440DB95DE',
+        blockCreated: 1274684,
+      },
+    },
+  },
+})
diff --git a/src/chains/definitions/redstone.ts b/src/chains/definitions/redstone.ts
index 5744066bec..fa766eafd2 100644
--- a/src/chains/definitions/redstone.ts
+++ b/src/chains/definitions/redstone.ts
@@ -1,13 +1,14 @@
+import { chainConfig } from '../../op-stack/chainConfig.js'
 import { defineChain } from '../../utils/chain/defineChain.js'
 
+const sourceId = 1 // Ethereum mainnet
+
 export const redstone = defineChain({
-  id: 690,
+  ...chainConfig,
   name: 'Redstone',
-  nativeCurrency: {
-    decimals: 18,
-    name: 'Ether',
-    symbol: 'ETH',
-  },
+  id: 690,
+  sourceId,
+  nativeCurrency: { decimals: 18, name: 'Ether', symbol: 'ETH' },
   rpcUrls: {
     default: {
       http: ['https://rpc.redstonechain.com'],
@@ -15,6 +16,33 @@ export const redstone = defineChain({
     },
   },
   blockExplorers: {
-    default: { name: 'Explorer', url: '	https://explorer.redstone.xyz' },
+    default: {
+      name: 'Blockscout',
+      url: 'https://explorer.redstone.xyz',
+    },
+  },
+  contracts: {
+    ...chainConfig.contracts,
+    multicall3: {
+      address: '0xca11bde05977b3631167028862be2a173976ca11',
+    },
+    portal: {
+      [sourceId]: {
+        address: '0xC7bCb0e8839a28A1cFadd1CF716de9016CdA51ae',
+        blockCreated: 19578329,
+      },
+    },
+    l2OutputOracle: {
+      [sourceId]: {
+        address: '0xa426A052f657AEEefc298b3B5c35a470e4739d69',
+        blockCreated: 19578337,
+      },
+    },
+    l1StandardBridge: {
+      [sourceId]: {
+        address: '0xc473ca7E02af24c129c2eEf51F2aDf0411c1Df69',
+        blockCreated: 19578331,
+      },
+    },
   },
 })
diff --git a/src/chains/index.ts b/src/chains/index.ts
index 4bc0c0411e..53a8065091 100644
--- a/src/chains/index.ts
+++ b/src/chains/index.ts
@@ -129,6 +129,7 @@ export { iotexTestnet } from './definitions/iotexTestnet.js'
 export { jbc } from './definitions/jbc.js'
 export { jbcTestnet } from './definitions/jbcTestnet.js'
 export { karura } from './definitions/karura.js'
+export { garnet } from './definitions/garnet.js'
 export { gobi } from './definitions/gobi.js'
 export { goerli } from './definitions/goerli.js'
 export { gnosis } from './definitions/gnosis.js'