diff --git a/.yarn/cache/meriyah-npm-4.3.7-18d2504ccb-537fed1981.zip b/.yarn/cache/meriyah-npm-4.3.7-18d2504ccb-537fed1981.zip
deleted file mode 100644
index f75dac6d..00000000
Binary files a/.yarn/cache/meriyah-npm-4.3.7-18d2504ccb-537fed1981.zip and /dev/null differ
diff --git a/.yarn/cache/meriyah-npm-5.0.0-2cc74cfe0a-bdd628ab95.zip b/.yarn/cache/meriyah-npm-5.0.0-2cc74cfe0a-bdd628ab95.zip
new file mode 100644
index 00000000..4200bdac
Binary files /dev/null and b/.yarn/cache/meriyah-npm-5.0.0-2cc74cfe0a-bdd628ab95.zip differ
diff --git a/package.json b/package.json
index 9839bd92..61320f16 100644
--- a/package.json
+++ b/package.json
@@ -90,7 +90,7 @@
     "astring": "^1.8.6",
     "chalk": "<5",
     "json5": "^2.2.3",
-    "meriyah": "^4.3.7",
+    "meriyah": "^5.0.0",
     "source-map-js": "^1.0.2",
     "stack-utils": "^2.0.6",
     "yaml": "^2.3.4"
diff --git a/src/config.ts b/src/config.ts
index ed959f8d..b4f63c06 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -128,6 +128,10 @@ export class Config {
     };
   }
 
+  // For easily toggling features/fixes for testing.
+  readonly addJsonImportAttributes = true;
+  readonly fixJsonImportAssertions = true;
+
   migrate() {
     if (!this.migrationPending) return;
 
diff --git a/src/loader.ts b/src/loader.ts
index 6b68cfd1..ca1ac13b 100644
--- a/src/loader.ts
+++ b/src/loader.ts
@@ -48,7 +48,17 @@ export const load: NodeLoaderHooksAPI2["load"] = async function load(url, contex
     const original = await defaultLoad(url, context, defaultLoad);
 
     if (original.source) {
-      const xformed = transform(original.source.toString(), new URL(url));
+      let xformed = transform(original.source.toString(), new URL(url));
+
+      if (config.addJsonImportAttributes) {
+        // Add import attributes to json imports if they don't have it.
+        // Import-attributes is lost after generating the instrumented
+        // code from the AST with the Astring library.
+        const regex = /(import\s+\w+\s+from\s+['"][^'"]+\.json['"])\s*;/g;
+        xformed = xformed.replace(regex, (match, importPart) => {
+          return `${importPart} with {type: "json"};`;
+        });
+      }
 
       return {
         shortCircuit: false,
diff --git a/src/transform.ts b/src/transform.ts
index 860b2803..c8844700 100644
--- a/src/transform.ts
+++ b/src/transform.ts
@@ -14,6 +14,7 @@ import * as mocha from "./hooks/mocha";
 import * as next from "./hooks/next";
 import * as vitest from "./hooks/vitest";
 import { warn } from "./message";
+import config from "./config";
 
 const debug = debuglog("appmap");
 const treeDebug = debuglog("appmap-tree");
@@ -41,6 +42,14 @@ export default function transform(code: string, url: URL, hooks = defaultHooks):
 
   if (hooks.some((h) => h.shouldIgnore?.(url))) return code;
 
+  if (config.fixJsonImportAssertions) {
+    // Meriyah does not support old import-assertions.
+    // Replace import-assertions with the import-attributes syntax
+    // for json imports.
+    const regex = /assert\s*\{\s*type\s*:\s*"json"\s*\}/g;
+    code = code.replace(regex, 'with {type: "json"}');
+  }
+
   try {
     const comments: ESTree.Comment[] = [];
     const tree = parse(code, {
diff --git a/test/__snapshots__/simple.test.ts.snap b/test/__snapshots__/simple.test.ts.snap
index 00d03c66..f8908ab5 100644
--- a/test/__snapshots__/simple.test.ts.snap
+++ b/test/__snapshots__/simple.test.ts.snap
@@ -277,6 +277,70 @@ exports[`mapping a custom Error class with a message property 1`] = `
 }
 `;
 
+exports[`mapping a script with import attributes/assertions 1`] = `
+{
+  "classMap": [
+    {
+      "children": [
+        {
+          "children": [
+            {
+              "location": "importAttributes.mjs:3",
+              "name": "helloWorld",
+              "static": true,
+              "type": "function",
+            },
+          ],
+          "name": "importAttributes",
+          "type": "class",
+        },
+      ],
+      "name": "simple",
+      "type": "package",
+    },
+  ],
+  "events": [
+    {
+      "defined_class": "importAttributes",
+      "event": "call",
+      "id": 1,
+      "lineno": 3,
+      "method_id": "helloWorld",
+      "parameters": [],
+      "path": "importAttributes.mjs",
+      "static": true,
+      "thread_id": 0,
+    },
+    {
+      "elapsed": 31.337,
+      "event": "return",
+      "id": 2,
+      "parent_id": 1,
+      "thread_id": 0,
+    },
+  ],
+  "metadata": {
+    "app": "simple",
+    "client": {
+      "name": "appmap-node",
+      "url": "https://github.com/getappmap/appmap-node",
+      "version": "test node-appmap version",
+    },
+    "language": {
+      "engine": "Node.js",
+      "name": "javascript",
+      "version": "test node version",
+    },
+    "name": "test process recording",
+    "recorder": {
+      "name": "process",
+      "type": "process",
+    },
+  },
+  "version": "1.12",
+}
+`;
+
 exports[`mapping a simple script 1`] = `
 {
   "classMap": [
diff --git a/test/simple.test.ts b/test/simple.test.ts
index ff1a421a..63c628a3 100644
--- a/test/simple.test.ts
+++ b/test/simple.test.ts
@@ -27,6 +27,11 @@ integrationTest("mapping an mjs script", () => {
   expect(readAppmap()).toMatchSnapshot();
 });
 
+integrationTest("mapping a script with import attributes/assertions", () => {
+  expect(runAppmapNode("importAttributes.mjs").status).toBe(0);
+  expect(readAppmap()).toMatchSnapshot();
+});
+
 integrationTest("mapping js class methods and constructors containing super keyword", () => {
   expect(runAppmapNode("class.js").status).toBe(0);
   expect(readAppmap()).toMatchSnapshot();
diff --git a/test/simple/importAttributes.json b/test/simple/importAttributes.json
new file mode 100644
index 00000000..b42e2f20
--- /dev/null
+++ b/test/simple/importAttributes.json
@@ -0,0 +1,3 @@
+{
+    "content": "This is for the import attributes test"
+}
\ No newline at end of file
diff --git a/test/simple/importAttributes.mjs b/test/simple/importAttributes.mjs
new file mode 100644
index 00000000..3be46bf8
--- /dev/null
+++ b/test/simple/importAttributes.mjs
@@ -0,0 +1,7 @@
+import importedJson from "./importAttributes.json" assert { type: "json" };
+
+export function helloWorld() {
+  console.log(importedJson);
+}
+
+helloWorld();
diff --git a/yarn.lock b/yarn.lock
index 0b593205..3fce350c 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2774,7 +2774,7 @@ __metadata:
     fast-glob: ^3.3.1
     jest: ^29.6.2
     json5: ^2.2.3
-    meriyah: ^4.3.7
+    meriyah: ^5.0.0
     mongodb: ^6.3.0
     next: ^14.0.4
     prettier: ^3.0.2
@@ -6854,10 +6854,10 @@ __metadata:
   languageName: node
   linkType: hard
 
-"meriyah@npm:^4.3.7":
-  version: 4.3.7
-  resolution: "meriyah@npm:4.3.7"
-  checksum: 537fed1981bb4c2dc5fffa0c2d159fc169bff252e7a31c8b15ce3ddb9e91d8b66cacf5c932d7fc31bd522dd70d9b007e19131ac40172cd3bd27feee79c447041
+"meriyah@npm:^5.0.0":
+  version: 5.0.0
+  resolution: "meriyah@npm:5.0.0"
+  checksum: bdd628ab956fca90d44334cc4538cdcde73bff5cf64c32aee3ddce808fe77591fcd6e6c141ec0fc5a6451776f55f6600cdcc53643b106a9e09974f169c697961
   languageName: node
   linkType: hard