diff --git a/.changeset/swift-terms-protect.md b/.changeset/swift-terms-protect.md
new file mode 100644
index 0000000000..517d05f813
--- /dev/null
+++ b/.changeset/swift-terms-protect.md
@@ -0,0 +1,8 @@
+---
+"@wagmi/connectors": minor
+"wagmi": minor
+"@wagmi/core": minor
+"@wagmi/vue": minor
+---
+
+Removed simulation in `writeContract` & `sendTransaction`.
diff --git a/packages/connectors/src/coinbaseWallet.ts b/packages/connectors/src/coinbaseWallet.ts
index 8793703f8a..50f732d2c9 100644
--- a/packages/connectors/src/coinbaseWallet.ts
+++ b/packages/connectors/src/coinbaseWallet.ts
@@ -91,7 +91,6 @@ function version4(parameters: Version4Parameters) {
     id: 'coinbaseWalletSDK',
     name: 'Coinbase Wallet',
     rdns: 'com.coinbase.wallet',
-    supportsSimulation: true,
     type: coinbaseWallet.type,
     async connect({ chainId } = {}) {
       try {
@@ -324,7 +323,6 @@ function version3(parameters: Version3Parameters) {
   return createConnector<Provider>((config) => ({
     id: 'coinbaseWalletSDK',
     name: 'Coinbase Wallet',
-    supportsSimulation: true,
     type: coinbaseWallet.type,
     async connect({ chainId } = {}) {
       try {
diff --git a/packages/core/src/actions/codegen/createSimulateContract.test-d.ts b/packages/core/src/actions/codegen/createSimulateContract.test-d.ts
index 763436bc78..91e5998977 100644
--- a/packages/core/src/actions/codegen/createSimulateContract.test-d.ts
+++ b/packages/core/src/actions/codegen/createSimulateContract.test-d.ts
@@ -21,7 +21,6 @@ test('default', async () => {
   expectTypeOf(result).toMatchTypeOf<{
     result: boolean
     request: {
-      __mode: 'prepared'
       chainId: 1
       abi: readonly [
         {
@@ -126,7 +125,6 @@ test('functionName', async () => {
   expectTypeOf(result).toMatchTypeOf<{
     result: boolean
     request: {
-      __mode: 'prepared'
       chainId: 1
       abi: readonly [
         {
diff --git a/packages/core/src/actions/codegen/createSimulateContract.test.ts b/packages/core/src/actions/codegen/createSimulateContract.test.ts
index af7aa0f976..bd37d13770 100644
--- a/packages/core/src/actions/codegen/createSimulateContract.test.ts
+++ b/packages/core/src/actions/codegen/createSimulateContract.test.ts
@@ -23,7 +23,6 @@ test('default', async () => {
     {
       "chainId": 1,
       "request": {
-        "__mode": "prepared",
         "abi": [
           {
             "inputs": [],
@@ -70,7 +69,6 @@ test('multichain', async () => {
     {
       "chainId": 456,
       "request": {
-        "__mode": "prepared",
         "abi": [
           {
             "inputs": [],
@@ -112,7 +110,6 @@ test('functionName', async () => {
     {
       "chainId": 1,
       "request": {
-        "__mode": "prepared",
         "abi": [
           {
             "inputs": [],
diff --git a/packages/core/src/actions/codegen/createWriteContract.ts b/packages/core/src/actions/codegen/createWriteContract.ts
index d886ad6a30..6c1d891a3f 100644
--- a/packages/core/src/actions/codegen/createWriteContract.ts
+++ b/packages/core/src/actions/codegen/createWriteContract.ts
@@ -86,7 +86,10 @@ export type CreateWriteContractReturnType<
               | undefined
           }
         : Compute<ChainIdParameter<config, chainId>>) &
-      ConnectorParameter & { __mode?: 'prepared' }
+      ConnectorParameter & {
+        /** @deprecated */
+        __mode?: 'prepared'
+      }
   >,
 ) => Promise<WriteContractReturnType>
 
diff --git a/packages/core/src/actions/sendTransaction.ts b/packages/core/src/actions/sendTransaction.ts
index 9531ea4f3c..9c8d1d7443 100644
--- a/packages/core/src/actions/sendTransaction.ts
+++ b/packages/core/src/actions/sendTransaction.ts
@@ -7,10 +7,7 @@ import type {
   SendTransactionParameters as viem_SendTransactionParameters,
   SendTransactionReturnType as viem_SendTransactionReturnType,
 } from 'viem'
-import {
-  estimateGas as viem_estimateGas,
-  sendTransaction as viem_sendTransaction,
-} from 'viem/actions'
+import { sendTransaction as viem_sendTransaction } from 'viem/actions'
 
 import type { Config } from '../createConfig.js'
 import type { BaseErrorType, ErrorType } from '../errors/base.js'
@@ -21,7 +18,6 @@ import type {
 } from '../types/properties.js'
 import type { Compute } from '../types/utils.js'
 import { getAction } from '../utils/getAction.js'
-import { getAccount } from './getAccount.js'
 import {
   type GetConnectorClientErrorType,
   getConnectorClient,
@@ -66,7 +62,7 @@ export async function sendTransaction<
   config: config,
   parameters: SendTransactionParameters<config, chainId>,
 ): Promise<SendTransactionReturnType> {
-  const { account, chainId, connector, gas: gas_, ...rest } = parameters
+  const { account, chainId, connector, ...rest } = parameters
 
   let client: Client
   if (typeof account === 'object' && account?.type === 'local')
@@ -78,37 +74,10 @@ export async function sendTransaction<
       connector,
     })
 
-  const { connector: activeConnector } = getAccount(config)
-
-  const gas = await (async () => {
-    // Skip gas estimation if `data` doesn't exist (not a contract interaction).
-    if (!('data' in parameters) || !parameters.data) return undefined
-
-    // Skip gas estimation if connector supports simulation.
-    if ((connector ?? activeConnector)?.supportsSimulation) return undefined
-
-    // Skip gas estimation if `null` is provided.
-    if (gas_ === null) return undefined
-
-    // Run gas estimation if no value is provided.
-    if (gas_ === undefined) {
-      const action = getAction(client, viem_estimateGas, 'estimateGas')
-      return action({
-        ...(rest as any),
-        account,
-        chain: chainId ? { id: chainId } : null,
-      })
-    }
-
-    // Use provided gas value.
-    return gas_
-  })()
-
   const action = getAction(client, viem_sendTransaction, 'sendTransaction')
   const hash = await action({
     ...(rest as any),
     ...(account ? { account } : {}),
-    gas,
     chain: chainId ? { id: chainId } : null,
   })
 
diff --git a/packages/core/src/actions/simulateContract.test-d.ts b/packages/core/src/actions/simulateContract.test-d.ts
index 6a485569da..3f893ff8f8 100644
--- a/packages/core/src/actions/simulateContract.test-d.ts
+++ b/packages/core/src/actions/simulateContract.test-d.ts
@@ -22,7 +22,6 @@ test('default', async () => {
   expectTypeOf(response).toMatchTypeOf<{
     result: boolean
     request: {
-      __mode: 'prepared'
       chainId: 1
       abi: readonly [
         {
diff --git a/packages/core/src/actions/simulateContract.test.ts b/packages/core/src/actions/simulateContract.test.ts
index 7857217592..a52cbd5568 100644
--- a/packages/core/src/actions/simulateContract.test.ts
+++ b/packages/core/src/actions/simulateContract.test.ts
@@ -19,7 +19,6 @@ test('parameters: account', async () => {
     {
       "chainId": 1,
       "request": {
-        "__mode": "prepared",
         "abi": [
           {
             "inputs": [],
@@ -58,7 +57,6 @@ test('parameters: connector', async () => {
     {
       "chainId": 1,
       "request": {
-        "__mode": "prepared",
         "abi": [
           {
             "inputs": [],
diff --git a/packages/core/src/actions/simulateContract.ts b/packages/core/src/actions/simulateContract.ts
index 6d9713ab18..e5fe5655ff 100644
--- a/packages/core/src/actions/simulateContract.ts
+++ b/packages/core/src/actions/simulateContract.ts
@@ -96,7 +96,7 @@ export type SimulateContractReturnType<
     chainId: chains[key]['id']
     request: Compute<
       PartialBy<
-        { __mode: 'prepared'; chainId: chainId; chain: chains[key] },
+        { chainId: chainId; chain: chains[key] },
         chainId extends config['chains'][number]['id'] ? never : 'chainId'
       >
     >
@@ -155,7 +155,7 @@ export async function simulateContract<
   return {
     chainId: client.chain.id,
     result,
-    request: { __mode: 'prepared', ...request, chainId },
+    request: { ...request, chainId },
   } as unknown as SimulateContractReturnType<
     abi,
     functionName,
diff --git a/packages/core/src/actions/writeContract.test-d.ts b/packages/core/src/actions/writeContract.test-d.ts
index ce3216ff6d..68009a3773 100644
--- a/packages/core/src/actions/writeContract.test-d.ts
+++ b/packages/core/src/actions/writeContract.test-d.ts
@@ -28,7 +28,6 @@ test('simulateContract', async () => {
   })
   await writeContract(config, request)
   await writeContract(config, {
-    __mode: 'prepared',
     address: '0x',
     abi: abi.erc20,
     functionName: 'transferFrom',
diff --git a/packages/core/src/actions/writeContract.ts b/packages/core/src/actions/writeContract.ts
index c68deb6e77..5fb6d87104 100644
--- a/packages/core/src/actions/writeContract.ts
+++ b/packages/core/src/actions/writeContract.ts
@@ -22,15 +22,10 @@ import type {
 } from '../types/properties.js'
 import type { Compute, UnionCompute } from '../types/utils.js'
 import { getAction } from '../utils/getAction.js'
-import { getAccount } from './getAccount.js'
 import {
   type GetConnectorClientErrorType,
   getConnectorClient,
 } from './getConnectorClient.js'
-import {
-  type SimulateContractErrorType,
-  simulateContract,
-} from './simulateContract.js'
 
 export type WriteContractParameters<
   abi extends Abi | readonly unknown[] = Abi,
@@ -64,7 +59,10 @@ export type WriteContractParameters<
     >
   }[number] &
     Compute<ChainIdParameter<config, chainId>> &
-    ConnectorParameter & { __mode?: 'prepared' }
+    ConnectorParameter & {
+      /** @deprecated */
+      __mode?: 'prepared'
+    }
 >
 
 export type WriteContractReturnType = viem_WriteContractReturnType
@@ -72,8 +70,6 @@ export type WriteContractReturnType = viem_WriteContractReturnType
 export type WriteContractErrorType =
   // getConnectorClient()
   | GetConnectorClientErrorType
-  // simulateContract()
-  | SimulateContractErrorType
   // base
   | BaseErrorType
   | ErrorType
@@ -95,7 +91,7 @@ export async function writeContract<
   config: config,
   parameters: WriteContractParameters<abi, functionName, args, config, chainId>,
 ): Promise<WriteContractReturnType> {
-  const { account, chainId, connector, __mode, ...rest } = parameters
+  const { account, chainId, connector, ...request } = parameters
 
   let client: Client
   if (typeof account === 'object' && account?.type === 'local')
@@ -107,23 +103,9 @@ export async function writeContract<
       connector,
     })
 
-  const { connector: activeConnector } = getAccount(config)
-
-  let request: any
-  if (__mode === 'prepared' || activeConnector?.supportsSimulation)
-    request = rest
-  else {
-    const { request: simulateRequest } = await simulateContract(config, {
-      ...rest,
-      account,
-      chainId,
-    } as any)
-    request = simulateRequest
-  }
-
   const action = getAction(client, viem_writeContract, 'writeContract')
   const hash = await action({
-    ...request,
+    ...(request as any),
     ...(account ? { account } : {}),
     chain: chainId ? { id: chainId } : null,
   })
diff --git a/packages/core/src/connectors/createConnector.ts b/packages/core/src/connectors/createConnector.ts
index 1724e8d765..b6ae1c2bad 100644
--- a/packages/core/src/connectors/createConnector.ts
+++ b/packages/core/src/connectors/createConnector.ts
@@ -38,6 +38,7 @@ export type CreateConnectorFn<
     readonly id: string
     readonly name: string
     readonly rdns?: string | readonly string[] | undefined
+    /** @deprecated */
     readonly supportsSimulation?: boolean | undefined
     readonly type: string
 
diff --git a/packages/core/src/connectors/injected.ts b/packages/core/src/connectors/injected.ts
index 7a7c41b51f..c9a9eae033 100644
--- a/packages/core/src/connectors/injected.ts
+++ b/packages/core/src/connectors/injected.ts
@@ -34,9 +34,6 @@ export type InjectedParameters = {
   unstable_shimAsyncInject?: boolean | number | undefined
 }
 
-// Regex of wallets/providers that can accurately simulate contract calls & display contract revert reasons.
-const supportsSimulationIdRegex = /(rabby|trustwallet)/
-
 injected.type = 'injected' as const
 export function injected(parameters: InjectedParameters = {}) {
   const { shimDisconnect = true, unstable_shimAsyncInject } = parameters
@@ -91,8 +88,9 @@ export function injected(parameters: InjectedParameters = {}) {
     get name() {
       return getTarget().name
     },
+    /** @deprecated */
     get supportsSimulation() {
-      return supportsSimulationIdRegex.test(this.id.toLowerCase())
+      return true
     },
     type: injected.type,
     async setup() {
diff --git a/packages/react/src/hooks/codegen/createUseSimulateContract.test-d.ts b/packages/react/src/hooks/codegen/createUseSimulateContract.test-d.ts
index 6a204737d2..5388e69109 100644
--- a/packages/react/src/hooks/codegen/createUseSimulateContract.test-d.ts
+++ b/packages/react/src/hooks/codegen/createUseSimulateContract.test-d.ts
@@ -19,7 +19,6 @@ test('default', () => {
     | {
         result: boolean
         request: {
-          __mode: 'prepared'
           chainId: 123
           abi: readonly [
             {
@@ -144,7 +143,6 @@ test('functionName', () => {
     | {
         result: boolean
         request: {
-          __mode: 'prepared'
           chainId: 123
           abi: readonly [
             {
diff --git a/packages/react/src/hooks/codegen/createUseSimulateContract.test.ts b/packages/react/src/hooks/codegen/createUseSimulateContract.test.ts
index 7bc4e4a941..c6e70b90ca 100644
--- a/packages/react/src/hooks/codegen/createUseSimulateContract.test.ts
+++ b/packages/react/src/hooks/codegen/createUseSimulateContract.test.ts
@@ -28,7 +28,6 @@ test('default', async () => {
       "data": {
         "chainId": 1,
         "request": {
-          "__mode": "prepared",
           "abi": [
             {
               "inputs": [],
@@ -116,7 +115,6 @@ test('multichain', async () => {
       "data": {
         "chainId": 456,
         "request": {
-          "__mode": "prepared",
           "abi": [
             {
               "inputs": [],
@@ -197,7 +195,6 @@ test('functionName', async () => {
       "data": {
         "chainId": 1,
         "request": {
-          "__mode": "prepared",
           "abi": [
             {
               "inputs": [],
diff --git a/packages/react/src/hooks/codegen/createUseWriteContract.ts b/packages/react/src/hooks/codegen/createUseWriteContract.ts
index 2680074d23..9e58fd973b 100644
--- a/packages/react/src/hooks/codegen/createUseWriteContract.ts
+++ b/packages/react/src/hooks/codegen/createUseWriteContract.ts
@@ -290,5 +290,8 @@ type Variables<
             | undefined
         }
       : Compute<ChainIdParameter<config, chainId>>) &
-    ConnectorParameter & { __mode?: 'prepared' }
+    ConnectorParameter & {
+      /** @deprecated */
+      __mode?: 'prepared'
+    }
 >
diff --git a/packages/react/src/hooks/useSimulateContract.test-d.ts b/packages/react/src/hooks/useSimulateContract.test-d.ts
index 38097fad5c..8159cdfccf 100644
--- a/packages/react/src/hooks/useSimulateContract.test-d.ts
+++ b/packages/react/src/hooks/useSimulateContract.test-d.ts
@@ -20,7 +20,6 @@ test('default', () => {
     | {
         result: boolean
         request: {
-          __mode: 'prepared'
           chainId?: undefined
           abi: readonly [
             {
@@ -82,7 +81,6 @@ test('UseSimulateContractReturnType', () => {
     | {
         result: boolean
         request: {
-          __mode: 'prepared'
           chainId: number
           abi: readonly [
             {
diff --git a/packages/react/src/hooks/useSimulateContract.test.ts b/packages/react/src/hooks/useSimulateContract.test.ts
index eb43bde1d9..3c785133c9 100644
--- a/packages/react/src/hooks/useSimulateContract.test.ts
+++ b/packages/react/src/hooks/useSimulateContract.test.ts
@@ -25,7 +25,6 @@ test('default', async () => {
       "data": {
         "chainId": 1,
         "request": {
-          "__mode": "prepared",
           "abi": [
             {
               "inputs": [],
diff --git a/packages/react/src/hooks/useWriteContract.test-d.ts b/packages/react/src/hooks/useWriteContract.test-d.ts
index d7240de04f..344c11255b 100644
--- a/packages/react/src/hooks/useWriteContract.test-d.ts
+++ b/packages/react/src/hooks/useWriteContract.test-d.ts
@@ -20,7 +20,6 @@ test('context', () => {
     mutation: {
       onMutate(variables) {
         expectTypeOf(variables).toMatchTypeOf<{
-          __mode?: 'prepared'
           chainId?: number | undefined
           abi: Abi
           functionName: string
@@ -33,7 +32,6 @@ test('context', () => {
         expectTypeOf(context).toEqualTypeOf<typeof contextValue | undefined>()
 
         expectTypeOf(variables).toMatchTypeOf<{
-          __mode?: 'prepared'
           chainId?: number | undefined
           abi: Abi
           functionName: string
@@ -45,7 +43,6 @@ test('context', () => {
         expectTypeOf(context).toEqualTypeOf<typeof contextValue>()
 
         expectTypeOf(variables).toMatchTypeOf<{
-          __mode?: 'prepared'
           chainId?: number | undefined
           abi: Abi
           functionName: string
@@ -58,7 +55,6 @@ test('context', () => {
         expectTypeOf(context).toEqualTypeOf<typeof contextValue | undefined>()
 
         expectTypeOf(variables).toMatchTypeOf<{
-          __mode?: 'prepared'
           chainId?: number | undefined
           abi: Abi
           functionName: string
@@ -89,7 +85,6 @@ test('context', () => {
         expectTypeOf(context).toEqualTypeOf<typeof contextValue | undefined>()
 
         expectTypeOf(variables).toMatchTypeOf<{
-          __mode?: 'prepared'
           chainId?: number | undefined
           abi: typeof abi.erc20
           functionName: 'transferFrom'
@@ -105,7 +100,6 @@ test('context', () => {
           readonly [Address, Address, bigint]
         >()
         expectTypeOf(variables).toMatchTypeOf<{
-          __mode?: 'prepared'
           chainId?: number | undefined
           abi: typeof abi.erc20
           functionName: 'transferFrom'
@@ -118,7 +112,6 @@ test('context', () => {
         expectTypeOf(context).toEqualTypeOf<typeof contextValue | undefined>()
 
         expectTypeOf(variables).toMatchTypeOf<{
-          __mode?: 'prepared'
           chainId?: number | undefined
           abi: typeof abi.erc20
           functionName: 'transferFrom'
diff --git a/packages/vue/src/composables/useSimulateContract.test-d.ts b/packages/vue/src/composables/useSimulateContract.test-d.ts
index 0eb2182edb..e8d2451caa 100644
--- a/packages/vue/src/composables/useSimulateContract.test-d.ts
+++ b/packages/vue/src/composables/useSimulateContract.test-d.ts
@@ -19,7 +19,6 @@ test('default', () => {
     | {
         result: boolean
         request: {
-          __mode: 'prepared'
           chainId?: undefined
           abi: readonly [
             {
@@ -74,7 +73,6 @@ test('UseSimulateContractReturnType', () => {
     | {
         result: boolean
         request: {
-          __mode: 'prepared'
           chainId: number
           abi: readonly [
             {
diff --git a/packages/vue/src/composables/useSimulateContract.test.ts b/packages/vue/src/composables/useSimulateContract.test.ts
index b93b829b65..1118a51d68 100644
--- a/packages/vue/src/composables/useSimulateContract.test.ts
+++ b/packages/vue/src/composables/useSimulateContract.test.ts
@@ -24,7 +24,6 @@ test('default', async () => {
     {
       "chainId": 1,
       "request": {
-        "__mode": "prepared",
         "abi": [
           {
             "inputs": [],
diff --git a/packages/vue/src/composables/useWriteContract.test-d.ts b/packages/vue/src/composables/useWriteContract.test-d.ts
index da3e1a5049..33a9b14342 100644
--- a/packages/vue/src/composables/useWriteContract.test-d.ts
+++ b/packages/vue/src/composables/useWriteContract.test-d.ts
@@ -19,7 +19,6 @@ test('context', () => {
     mutation: {
       onMutate(variables) {
         expectTypeOf(variables).toMatchTypeOf<{
-          __mode?: 'prepared'
           chainId?: number | undefined
           abi: Abi
           functionName: string
@@ -32,7 +31,6 @@ test('context', () => {
         expectTypeOf(context).toEqualTypeOf<typeof contextValue | undefined>()
 
         expectTypeOf(variables).toMatchTypeOf<{
-          __mode?: 'prepared'
           chainId?: number | undefined
           abi: Abi
           functionName: string
@@ -44,7 +42,6 @@ test('context', () => {
         expectTypeOf(context).toEqualTypeOf<typeof contextValue>()
 
         expectTypeOf(variables).toMatchTypeOf<{
-          __mode?: 'prepared'
           chainId?: number | undefined
           abi: Abi
           functionName: string
@@ -57,7 +54,6 @@ test('context', () => {
         expectTypeOf(context).toEqualTypeOf<typeof contextValue | undefined>()
 
         expectTypeOf(variables).toMatchTypeOf<{
-          __mode?: 'prepared'
           chainId?: number | undefined
           abi: Abi
           functionName: string
@@ -88,7 +84,6 @@ test('context', () => {
         expectTypeOf(context).toEqualTypeOf<typeof contextValue | undefined>()
 
         expectTypeOf(variables).toMatchTypeOf<{
-          __mode?: 'prepared'
           chainId?: number | undefined
           abi: typeof abi.erc20
           functionName: 'transferFrom'
@@ -104,7 +99,6 @@ test('context', () => {
           readonly [Address, Address, bigint]
         >()
         expectTypeOf(variables).toMatchTypeOf<{
-          __mode?: 'prepared'
           chainId?: number | undefined
           abi: typeof abi.erc20
           functionName: 'transferFrom'
@@ -117,7 +111,6 @@ test('context', () => {
         expectTypeOf(context).toEqualTypeOf<typeof contextValue | undefined>()
 
         expectTypeOf(variables).toMatchTypeOf<{
-          __mode?: 'prepared'
           chainId?: number | undefined
           abi: typeof abi.erc20
           functionName: 'transferFrom'
diff --git a/site/dev/creating-connectors.md b/site/dev/creating-connectors.md
index 0b98e834cf..c9e82b04b1 100644
--- a/site/dev/creating-connectors.md
+++ b/site/dev/creating-connectors.md
@@ -55,7 +55,6 @@ The type error tells you what properties are missing from `createConnector`'s re
 - `id`: The ID for the connector. This should be camel-cased and as short as possible. Example: `fooBarBaz`.
 - `name`: Human-readable name for the connector. Example: `'Foo Bar Baz'`.
 - `rdns`: Optional reverse DNS for the connector. This is used to filter out duplicate [EIP-6963](https://eips.ethereum.org/EIPS/eip-6963) injected providers when `createConfig#multiInjectedProviderDiscovery` is enabled.
-- `supportsSimulation`: Whether the connector supports contract simulation. This should be disabled if a connector's wallet cannot accurately simulate contract writes or display contract revert messages. Defaults to `false`.
 
 #### Methods