diff --git a/packages/solana/src/index.ts b/packages/solana/src/index.ts
index 2126a308c..6df071078 100644
--- a/packages/solana/src/index.ts
+++ b/packages/solana/src/index.ts
@@ -61,6 +61,7 @@ export class TurnkeySigner {
     tx: Transaction | VersionedTransaction,
     fromAddress: string,
     organizationId?: string,
+    timestampMs?: number,
   ) {
     const fromKey = new PublicKey(fromAddress);
     const messageToSign: Buffer = this.getMessageToSign(tx);
@@ -68,6 +69,7 @@ export class TurnkeySigner {
       messageToSign.toString("hex"),
       fromAddress,
       organizationId ?? this.organizationId,
+      timestampMs,
     );
     const signature = `${signRawPayloadResult?.r}${signRawPayloadResult?.s}`;
 
@@ -84,11 +86,13 @@ export class TurnkeySigner {
     message: Uint8Array,
     fromAddress: string,
     organizationId?: string,
+    timestampMs?: number,
   ): Promise<Uint8Array> {
     const signRawPayloadResult = await this.signRawPayload(
       Buffer.from(message).toString("hex"),
       fromAddress,
       organizationId,
+      timestampMs,
     );
     return Buffer.from(
       `${signRawPayloadResult?.r}${signRawPayloadResult?.s}`,
@@ -107,6 +111,7 @@ export class TurnkeySigner {
     tx: Transaction | VersionedTransaction,
     fromAddress: string,
     organizationId?: string,
+    timestampMs?: number,
   ): Promise<Transaction | VersionedTransaction> {
     const payloadToSign = Buffer.from(
       tx.serialize({
@@ -119,6 +124,7 @@ export class TurnkeySigner {
       payloadToSign,
       fromAddress,
       organizationId,
+      timestampMs,
     );
 
     const decodedTransaction = Buffer.from(signedTransaction, "hex");
@@ -135,12 +141,13 @@ export class TurnkeySigner {
     unsignedTransaction: string,
     signWith: string,
     organizationId?: string,
+    timestampMs?: number
   ) {
     if (this.client instanceof TurnkeyClient) {
       const response = await this.client.signTransaction({
         type: "ACTIVITY_TYPE_SIGN_TRANSACTION_V2",
         organizationId: organizationId ?? this.organizationId,
-        timestampMs: String(Date.now()),
+        timestampMs: timestampMs ? String(timestampMs) : String(Date.now()),
         parameters: {
           signWith,
           unsignedTransaction,
@@ -175,12 +182,13 @@ export class TurnkeySigner {
     payload: string,
     signWith: string,
     organizationId?: string,
+    timestampMs?: number,
   ) {
     if (this.client instanceof TurnkeyClient) {
       const response = await this.client.signRawPayload({
         type: "ACTIVITY_TYPE_SIGN_RAW_PAYLOAD_V2",
         organizationId: organizationId ?? this.organizationId,
-        timestampMs: String(Date.now()),
+        timestampMs: timestampMs ? String(timestampMs) : String(Date.now()),
         parameters: {
           signWith,
           payload,
@@ -221,12 +229,13 @@ export class TurnkeySigner {
     payloads: string[],
     signWith: string,
     organizationId?: string,
+    timestampMs?: number,
   ) {
     if (this.client instanceof TurnkeyClient) {
       const response = await this.client.signRawPayloads({
         type: "ACTIVITY_TYPE_SIGN_RAW_PAYLOADS",
         organizationId: organizationId ?? this.organizationId,
-        timestampMs: String(Date.now()),
+        timestampMs: timestampMs ? String(timestampMs) : String(Date.now()),
         parameters: {
           signWith,
           payloads,
diff --git a/packages/viem/src/index.ts b/packages/viem/src/index.ts
index f2bdfaf0d..3547c97b7 100644
--- a/packages/viem/src/index.ts
+++ b/packages/viem/src/index.ts
@@ -144,8 +144,8 @@ export function createAccountWithAddress(input: {
       transaction: TTransactionSerializable,
       options?: {
         serializer?:
-          | SerializeTransactionFn<TTransactionSerializable>
-          | undefined;
+        | SerializeTransactionFn<TTransactionSerializable>
+        | undefined;
       },
     ): Promise<Hex> {
       const serializer: SerializeTransactionFn<TTransactionSerializable> =
@@ -300,8 +300,8 @@ export async function createApiKeyAccount(
       transaction: TTransactionSerializable,
       options?: {
         serializer?:
-          | SerializeTransactionFn<TTransactionSerializable>
-          | undefined;
+        | SerializeTransactionFn<TTransactionSerializable>
+        | undefined;
       },
     ): Promise<Hex> {
       const serializer: SerializeTransactionFn<TTransactionSerializable> =
@@ -338,6 +338,7 @@ export async function signAuthorization(
   parameters: TSignAuthorizationParameters,
   organizationId: string,
   signWith: string,
+  timestampMs?: number,
 ): Promise<SignAuthorizationReturnType> {
   const { chainId, nonce, to = "object" } = parameters;
   const address = parameters.contractAddress ?? parameters.address;
@@ -360,6 +361,7 @@ export async function signAuthorization(
     organizationId,
     signWith,
     to,
+    timestampMs,
   );
 
   if (to === "object")
@@ -379,6 +381,7 @@ export async function signMessage(
   message: SignableMessage,
   organizationId: string,
   signWith: string,
+  timestampMs?: number,
 ): Promise<Hex> {
   const hashedMessage = hashMessage(message);
   const signedMessage = await signMessageWithErrorWrapping(
@@ -386,6 +389,8 @@ export async function signMessage(
     hashedMessage,
     organizationId,
     signWith,
+    undefined,
+    timestampMs,
   );
   return `${signedMessage}` as Hex;
 }
@@ -435,6 +440,7 @@ export async function signTypedData(
   data: TypedData | { [key: string]: unknown },
   organizationId: string,
   signWith: string,
+  timestampMs?: number,
 ): Promise<Hex> {
   const hashToSign = hashTypedData(data as HashTypedDataParameters);
 
@@ -444,6 +450,7 @@ export async function signTypedData(
     organizationId,
     signWith,
     "hex",
+    timestampMs,
   )) as Hex;
 }
 
@@ -452,6 +459,7 @@ async function signTransactionWithErrorWrapping(
   unsignedTransaction: string,
   organizationId: string,
   signWith: string,
+  timestampMs?: number
 ): Promise<Hex> {
   let signedTx: string;
   try {
@@ -460,6 +468,7 @@ async function signTransactionWithErrorWrapping(
       unsignedTransaction,
       organizationId,
       signWith,
+      timestampMs,
     );
   } catch (error: any) {
     // Wrap Turnkey error in Viem-specific error
@@ -492,6 +501,7 @@ async function signTransactionImpl(
   unsignedTransaction: string,
   organizationId: string,
   signWith: string,
+  timestampMs?: number
 ): Promise<string> {
   if (client instanceof TurnkeyClient) {
     const { activity } = await client.signTransaction({
@@ -502,7 +512,7 @@ async function signTransactionImpl(
         type: "TRANSACTION_TYPE_ETHEREUM",
         unsignedTransaction: unsignedTransaction,
       },
-      timestampMs: String(Date.now()), // millisecond timestamp
+      timestampMs: timestampMs ? String(timestampMs) : String(Date.now()), // millisecond timestamp
     });
 
     assertActivityCompleted(activity);
@@ -530,6 +540,7 @@ async function signMessageWithErrorWrapping(
   organizationId: string,
   signWith: string,
   to?: TSignatureFormat,
+  timestampMs?: number,
 ): Promise<TSignMessageResult> {
   let signedMessage: TSignMessageResult;
 
@@ -540,6 +551,7 @@ async function signMessageWithErrorWrapping(
       organizationId,
       signWith,
       to,
+      timestampMs,
     );
   } catch (error: any) {
     // Wrap Turnkey error in Viem-specific error
@@ -573,6 +585,7 @@ async function signMessageImpl(
   organizationId: string,
   signWith: string,
   to?: TSignatureFormat,
+  timestampMs?: number,
 ): Promise<TSignMessageResult> {
   let result: TSignature;
 
@@ -586,7 +599,7 @@ async function signMessageImpl(
         encoding: "PAYLOAD_ENCODING_HEXADECIMAL",
         hashFunction: "HASH_FUNCTION_NO_OP",
       },
-      timestampMs: String(Date.now()), // millisecond timestamp
+      timestampMs: timestampMs ? String(timestampMs) : String(Date.now()), // millisecond timestamp
     });
 
     assertActivityCompleted(activity);