diff --git a/.changeset/honest-emus-bet.md b/.changeset/honest-emus-bet.md
new file mode 100644
index 0000000000..30c8fc0aee
--- /dev/null
+++ b/.changeset/honest-emus-bet.md
@@ -0,0 +1,5 @@
+---
+"viem": patch
+---
+
+Added Core Blockchain Testnet details
diff --git a/src/chains/definitions/coreTestnet1.ts b/src/chains/definitions/coreTestnet1.ts
new file mode 100644
index 0000000000..1554f7e155
--- /dev/null
+++ b/src/chains/definitions/coreTestnet1.ts
@@ -0,0 +1,28 @@
+import { defineChain } from '../../utils/chain/defineChain.js'
+
+export const coreTestnet1 = /*#__PURE__*/ defineChain({
+  id: 1115,
+  name: 'Core Testnet',
+  nativeCurrency: {
+    decimals: 18,
+    name: 'tCore',
+    symbol: 'TCORE',
+  },
+  rpcUrls: {
+    default: { http: ['https://rpc.test.btcs.network'] },
+  },
+  blockExplorers: {
+    default: {
+      name: 'Core Testnet',
+      url: 'https://scan.test.btcs.network',
+      apiUrl:'https://api.test.btcs.network/api',
+    },
+  },
+  contracts: {
+    multicall3: {
+      address: '0xCcddF20A1932537123C2E48Bd8e00b108B8f7569',
+      blockCreated: 29_350_509, 
+    },
+  },
+  testnet: true,
+})
diff --git a/src/chains/definitions/coreTestnet2.ts b/src/chains/definitions/coreTestnet2.ts
new file mode 100644
index 0000000000..684c6480f5
--- /dev/null
+++ b/src/chains/definitions/coreTestnet2.ts
@@ -0,0 +1,28 @@
+import { defineChain } from '../../utils/chain/defineChain.js'
+
+export const coreTestnet2 = /*#__PURE__*/ defineChain({
+  id: 1114,
+  name: 'Core Testnet2',
+  nativeCurrency: {
+    decimals: 18,
+    name: 'tCore2',
+    symbol: 'TCORE2',
+  },
+  rpcUrls: {
+    default: { http: ['https://rpc.test2.btcs.network'] },
+  },
+  blockExplorers: {
+    default: {
+      name: 'Core Testnet2',
+      url: 'https://scan.test2.btcs.network',
+      apiUrl:'https://api.test2.btcs.network/api',
+    },
+  },
+  contracts: {
+    multicall3: {
+      address: '0x3CB285ff3Cd5C7C7e570b1E7DE3De17A0f985e56',
+      blockCreated: 3_838_600, 
+    },
+  },
+  testnet: true,
+})
diff --git a/src/chains/index.ts b/src/chains/index.ts
index 2f84929b8a..bc2b8ebe5a 100644
--- a/src/chains/index.ts
+++ b/src/chains/index.ts
@@ -98,6 +98,8 @@ export { coinex } from './definitions/coinex.js'
 export { confluxESpace } from './definitions/confluxESpace.js'
 export { confluxESpaceTestnet } from './definitions/confluxESpaceTestnet.js'
 export { coreDao } from './definitions/coreDao.js'
+export { coreTestnet1 } from './definitions/coreTestnet1.js'
+export { coreTestnet2 } from './definitions/coreTestnet2.js'
 export { corn } from './definitions/corn.js'
 export { cornTestnet } from './definitions/cornTestnet.js'
 export { crab } from './definitions/crab.js'