diff --git a/sdk/js-query/CHANGELOG.md b/sdk/js-query/CHANGELOG.md
index 610f83fcf2..983bd8da97 100644
--- a/sdk/js-query/CHANGELOG.md
+++ b/sdk/js-query/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.0.7
+
+Add EthCallByTimestamp mock support
+
 ## 0.0.6
 
 Deserialization support
diff --git a/sdk/js-query/package.json b/sdk/js-query/package.json
index a21fd5f814..22ed382ebd 100644
--- a/sdk/js-query/package.json
+++ b/sdk/js-query/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@wormhole-foundation/wormhole-query-sdk",
-  "version": "0.0.6",
+  "version": "0.0.7",
   "description": "Wormhole cross-chain query SDK",
   "homepage": "https://wormhole.com",
   "main": "./lib/cjs/index.js",
diff --git a/sdk/js-query/src/mock/index.ts b/sdk/js-query/src/mock/index.ts
index 5276cd282e..e1fd296abf 100644
--- a/sdk/js-query/src/mock/index.ts
+++ b/sdk/js-query/src/mock/index.ts
@@ -2,6 +2,8 @@ import axios from "axios";
 import { Buffer } from "buffer";
 import {
   ChainQueryType,
+  EthCallByTimestampQueryRequest,
+  EthCallByTimestampQueryResponse,
   EthCallQueryRequest,
   EthCallQueryResponse,
   EthCallWithFinalityQueryRequest,
@@ -202,6 +204,150 @@ export class QueryProxyMock {
             )
           )
         );
+      } else if (type === ChainQueryType.EthCallByTimeStamp) {
+        const query = perChainRequest.query as EthCallByTimestampQueryRequest;
+        // Verify that the two block hints are consistent, either both set, or both unset.
+        if (
+          (query.targetBlockHint === "") !==
+          (query.followingBlockHint === "")
+        ) {
+          throw new Error(
+            `Invalid block id hints in eth_call_by_timestamp query request, both should be either set or unset`
+          );
+        }
+        let targetBlock = query.targetBlockHint;
+        let followingBlock = query.followingBlockHint;
+        if (targetBlock === "") {
+          let nextQueryBlock = "latest";
+          let tries = 0;
+          let targetTimestamp = BigInt(0);
+          let followingTimestamp = BigInt(0);
+          while (
+            query.targetTimestamp < targetTimestamp ||
+            query.targetTimestamp >= followingTimestamp
+          ) {
+            if (tries > 128) {
+              throw new Error(`Timestamp was not within the last 128 blocks.`);
+            }
+            // TODO: batching
+            const blockResult = (
+              await axios.post(rpc, {
+                jsonrpc: "2.0",
+                id: 1,
+                method: "eth_getBlockByNumber",
+                params: [nextQueryBlock, false],
+              })
+            ).data?.result;
+            if (!blockResult) {
+              throw new Error(
+                `Invalid block result while searching for timestamp of ${nextQueryBlock}`
+              );
+            }
+            followingBlock = targetBlock;
+            followingTimestamp = targetTimestamp;
+            targetBlock = blockResult.number;
+            targetTimestamp =
+              BigInt(parseInt(blockResult.timestamp.substring(2), 16)) *
+              BigInt("1000000"); // time in seconds -> microseconds
+            nextQueryBlock = `0x${(
+              BigInt(blockResult.number) - BigInt(1)
+            ).toString(16)}`;
+            tries++;
+          }
+        }
+        const response = await axios.post(rpc, [
+          ...query.callData.map((args, idx) => ({
+            jsonrpc: "2.0",
+            id: idx,
+            method: "eth_call",
+            params: [
+              args,
+              //TODO: support block hash
+              targetBlock,
+            ],
+          })),
+          {
+            jsonrpc: "2.0",
+            id: query.callData.length,
+            method: "eth_getBlockByNumber",
+            params: [targetBlock, false],
+          },
+          {
+            jsonrpc: "2.0",
+            id: query.callData.length,
+            method: "eth_getBlockByNumber",
+            params: [followingBlock, false],
+          },
+        ]);
+        const callResults = response?.data?.slice(0, query.callData.length);
+        const targetBlockResult =
+          response?.data?.[query.callData.length]?.result;
+        const followingBlockResult =
+          response?.data?.[query.callData.length + 1]?.result;
+        if (
+          !targetBlockResult ||
+          !targetBlockResult.number ||
+          !targetBlockResult.timestamp ||
+          !targetBlockResult.hash
+        ) {
+          throw new Error(
+            `Invalid target block result for chain ${perChainRequest.chainId} block ${query.targetBlockHint}`
+          );
+        }
+        if (
+          !followingBlockResult ||
+          !followingBlockResult.number ||
+          !followingBlockResult.timestamp ||
+          !followingBlockResult.hash
+        ) {
+          throw new Error(
+            `Invalid following block result for chain ${perChainRequest.chainId} tag ${query.followingBlockHint}`
+          );
+        }
+        /*
+          target_block.timestamp <= target_time < following_block.timestamp
+          and
+          following_block_num - 1 == target_block_num
+        */
+        const targetBlockNumber = BigInt(
+          parseInt(targetBlockResult.number.substring(2), 16)
+        );
+        const followingBlockNumber = BigInt(
+          parseInt(followingBlockResult.number.substring(2), 16)
+        );
+        if (targetBlockNumber + BigInt(1) !== followingBlockNumber) {
+          throw new Error(
+            `eth_call_by_timestamp query blocks are not adjacent`
+          );
+        }
+        const targetTimestamp =
+          BigInt(parseInt(targetBlockResult.timestamp.substring(2), 16)) *
+          BigInt("1000000"); // time in seconds -> microseconds
+        const followingTimestamp =
+          BigInt(parseInt(followingBlockResult.timestamp.substring(2), 16)) *
+          BigInt("1000000"); // time in seconds -> microseconds
+        if (
+          query.targetTimestamp < targetTimestamp ||
+          query.targetTimestamp >= followingTimestamp
+        ) {
+          throw new Error(
+            `eth_call_by_timestamp desired timestamp falls outside of block range`
+          );
+        }
+        queryResponse.responses.push(
+          new PerChainQueryResponse(
+            perChainRequest.chainId,
+            new EthCallByTimestampQueryResponse(
+              BigInt(parseInt(targetBlockResult.number.substring(2), 16)), // block number
+              targetBlockResult.hash, // hash
+              targetTimestamp,
+              BigInt(parseInt(followingBlockResult.number.substring(2), 16)), // block number
+              followingBlockResult.hash, // hash
+              followingTimestamp,
+              callResults.map((callResult: any) => callResult.result)
+            )
+          )
+        );
       } else {
         throw new Error(`Unsupported query type for mock: ${type}`);
       }
diff --git a/sdk/js-query/src/mock/mock.test.ts b/sdk/js-query/src/mock/mock.test.ts
index 03201422d1..24671b75fe 100644
--- a/sdk/js-query/src/mock/mock.test.ts
+++ b/sdk/js-query/src/mock/mock.test.ts
@@ -9,6 +9,7 @@ import {
 import axios from "axios";
 import { eth } from "web3";
 import {
+  EthCallByTimestampQueryRequest,
   EthCallQueryRequest,
   EthCallWithFinalityQueryRequest,
   PerChainQueryRequest,
@@ -127,4 +128,108 @@ describe.skip("mocks match testnet", () => {
     // const matchesReal = mock.sign(serializedResponse);
     // expect(matchesReal).toEqual(realResponse.signatures);
   });
+  test("EthCallByTimestampQueryRequest mock matches testnet", async () => {
+    const targetTimestamp =
+      BigInt(Date.now() - 1000 * 30) * // thirty seconds ago
+      BigInt(1000); // milliseconds to microseconds
+    const arbitrumDemoContract = "0x6E36177f26A3C9cD2CE8DDF1b12904fe36deA47F";
+    const data = eth.abi.encodeFunctionSignature("getMyCounter()");
+    const query = new QueryRequest(42, [
+      new PerChainQueryRequest(
+        23,
+        new EthCallByTimestampQueryRequest(targetTimestamp, "", "", [
+          { to: arbitrumDemoContract, data },
+        ])
+      ),
+    ]);
+    const { bytes } = await mock.mock(query);
+    // from CCQ Demo UI
+    const signatureNotRequiredApiKey = "2d6c22c6-afae-4e54-b36d-5ba118da646a";
+    const realResponse = (
+      await axios.post<QueryProxyQueryResponse>(
+        QUERY_URL,
+        {
+          bytes: Buffer.from(query.serialize()).toString("hex"),
+        },
+        { headers: { "X-API-Key": signatureNotRequiredApiKey } }
+      )
+    ).data;
+    // the mock has an empty request signature, whereas the real service is signed
+    // we'll empty out the sig to compare the bytes
+    const realResponseWithEmptySignature = `${realResponse.bytes.substring(
+      0,
+      6
+    )}${Buffer.from(new Array(65)).toString(
+      "hex"
+    )}${realResponse.bytes.substring(6 + 65 * 2)}`;
+    expect(bytes).toEqual(realResponseWithEmptySignature);
+  });
+  test("EthCallByTimestampQueryRequest fails with non-adjacent blocks", async () => {
+    expect.assertions(1);
+    const targetTimestamp =
+      BigInt(Date.now() - 1000 * 60 * 1) * // one minute ago
+      BigInt(1000); // milliseconds to microseconds
+    const blockNumber = (
+      await axios.post(ARBITRUM_NODE_URL, {
+        jsonrpc: "2.0",
+        id: 1,
+        method: "eth_getBlockByNumber",
+        params: ["finalized", false],
+      })
+    ).data?.result?.number;
+    const arbitrumDemoContract = "0x6E36177f26A3C9cD2CE8DDF1b12904fe36deA47F";
+    const data = eth.abi.encodeFunctionSignature("getMyCounter()");
+    const query = new QueryRequest(42, [
+      new PerChainQueryRequest(
+        23,
+        new EthCallByTimestampQueryRequest(
+          targetTimestamp,
+          blockNumber,
+          blockNumber,
+          [{ to: arbitrumDemoContract, data }]
+        )
+      ),
+    ]);
+    try {
+      await mock.mock(query);
+    } catch (e: any) {
+      expect(e.message).toMatch(
+        "eth_call_by_timestamp query blocks are not adjacent"
+      );
+    }
+  });
+  test("EthCallByTimestampQueryRequest fails with wrong timestamp", async () => {
+    expect.assertions(1);
+    const targetTimestamp =
+      BigInt(Date.now() - 1000 * 60 * 30) * // thirty minutes ago
+      BigInt(1000); // milliseconds to microseconds
+    const blockNumber = (
+      await axios.post(ARBITRUM_NODE_URL, {
+        jsonrpc: "2.0",
+        id: 1,
+        method: "eth_getBlockByNumber",
+        params: ["finalized", false],
+      })
+    ).data?.result?.number;
+    const arbitrumDemoContract = "0x6E36177f26A3C9cD2CE8DDF1b12904fe36deA47F";
+    const data = eth.abi.encodeFunctionSignature("getMyCounter()");
+    const query = new QueryRequest(42, [
+      new PerChainQueryRequest(
+        23,
+        new EthCallByTimestampQueryRequest(
+          targetTimestamp,
+          blockNumber,
+          `0x${(parseInt(blockNumber, 16) + 1).toString(16)}`,
+          [{ to: arbitrumDemoContract, data }]
+        )
+      ),
+    ]);
+    try {
+      await mock.mock(query);
+    } catch (e: any) {
+      expect(e.message).toMatch(
+        "eth_call_by_timestamp desired timestamp falls outside of block range"
+      );
+    }
+  });
 });