diff --git a/.changeset/rare-goats-yell.md b/.changeset/rare-goats-yell.md
new file mode 100644
index 0000000000..4c760529d9
--- /dev/null
+++ b/.changeset/rare-goats-yell.md
@@ -0,0 +1,5 @@
+---
+"viem": patch
+---
+
+Removed redundant `eth_getBlockByNumber` calls.
diff --git a/src/actions/wallet/prepareTransactionRequest.test.ts b/src/actions/wallet/prepareTransactionRequest.test.ts
index 46da196191..571649cd6e 100644
--- a/src/actions/wallet/prepareTransactionRequest.test.ts
+++ b/src/actions/wallet/prepareTransactionRequest.test.ts
@@ -13,7 +13,10 @@ import { parseGwei } from '../../utils/unit/parseGwei.js'
 import { anvilMainnet } from '../../../test/src/anvil.js'
 import { http, createClient, toBlobs } from '../../index.js'
 import { nonceManager } from '../../utils/index.js'
-import { prepareTransactionRequest } from './prepareTransactionRequest.js'
+import {
+  eip1559NetworkCache,
+  prepareTransactionRequest,
+} from './prepareTransactionRequest.js'
 
 const client = anvilMainnet.getClient()
 
@@ -65,6 +68,8 @@ test('default', async () => {
 test('legacy fees', async () => {
   await setup()
 
+  eip1559NetworkCache.clear()
+
   vi.spyOn(getBlock, 'getBlock').mockResolvedValueOnce({
     baseFeePerGas: undefined,
   } as any)
@@ -100,6 +105,8 @@ test('legacy fees', async () => {
       "value": 1000000000000000000n,
     }
   `)
+
+  eip1559NetworkCache.clear()
 })
 
 test('args: account', async () => {
@@ -253,8 +260,6 @@ test('args: nonce', async () => {
 test('args: gasPrice', async () => {
   await setup()
 
-  vi.spyOn(getBlock, 'getBlock').mockResolvedValueOnce({} as any)
-
   const { nonce: _nonce, ...request } = await prepareTransactionRequest(
     client,
     {
diff --git a/src/actions/wallet/prepareTransactionRequest.ts b/src/actions/wallet/prepareTransactionRequest.ts
index d99523d93c..0c41b5ccd4 100644
--- a/src/actions/wallet/prepareTransactionRequest.ts
+++ b/src/actions/wallet/prepareTransactionRequest.ts
@@ -76,6 +76,9 @@ export const defaultParameters = [
   'type',
 ] as const
 
+/** @internal */
+export const eip1559NetworkCache = /*#__PURE__*/ new Map<string, boolean>()
+
 export type PrepareTransactionRequestParameterType =
   | 'blobVersionedHashes'
   | 'chainId'
@@ -325,10 +328,13 @@ export async function prepareTransactionRequest<
         request as TransactionSerializable,
       ) as any
     } catch {
-      // infer type from block
-      const block = await getBlock()
-      request.type =
-        typeof block?.baseFeePerGas === 'bigint' ? 'eip1559' : 'legacy'
+      let isEip1559Network = eip1559NetworkCache.get(client.uid)
+      if (typeof isEip1559Network === 'undefined') {
+        const block = await getBlock()
+        isEip1559Network = typeof block?.baseFeePerGas === 'bigint'
+        eip1559NetworkCache.set(client.uid, isEip1559Network)
+      }
+      request.type = isEip1559Network ? 'eip1559' : 'legacy'
     }
   }
 
@@ -369,17 +375,19 @@ export async function prepareTransactionRequest<
       )
         throw new Eip1559FeesNotSupportedError()
 
-      const block = await getBlock()
-      const { gasPrice: gasPrice_ } = await internal_estimateFeesPerGas(
-        client,
-        {
-          block: block as Block,
-          chain,
-          request: request as PrepareTransactionRequestParameters,
-          type: 'legacy',
-        },
-      )
-      request.gasPrice = gasPrice_
+      if (typeof args.gasPrice === 'undefined') {
+        const block = await getBlock()
+        const { gasPrice: gasPrice_ } = await internal_estimateFeesPerGas(
+          client,
+          {
+            block: block as Block,
+            chain,
+            request: request as PrepareTransactionRequestParameters,
+            type: 'legacy',
+          },
+        )
+        request.gasPrice = gasPrice_
+      }
     }
   }