diff --git a/test/wpt/runner/runner/runner.mjs b/test/wpt/runner/runner/runner.mjs
index 1a17ca6f7a0..ba8c75e6893 100644
--- a/test/wpt/runner/runner/runner.mjs
+++ b/test/wpt/runner/runner/runner.mjs
@@ -1,15 +1,34 @@
 import { deepStrictEqual } from 'node:assert'
 import { EventEmitter, once } from 'node:events'
-import { readdirSync, readFileSync, statSync } from 'node:fs'
+import { readdirSync, readFileSync, statSync, writeFileSync } from 'node:fs'
 import { basename, isAbsolute, join, resolve } from 'node:path'
 import { fileURLToPath } from 'node:url'
 import { Worker } from 'node:worker_threads'
 import { parseMeta, handlePipes, normalizeName, colors } from './util.mjs'
 
+const { WPT_REPORT } = process.env
 const basePath = fileURLToPath(join(import.meta.url, '../../..'))
 const testPath = join(basePath, 'tests')
 const statusPath = join(basePath, 'status')
 
+// https://github.com/web-platform-tests/wpt/blob/b24eedd/resources/testharness.js#L3705
+function sanitizeUnpairedSurrogates (str) {
+  return str.replace(
+    /([\ud800-\udbff]+)(?![\udc00-\udfff])|(^|[^\ud800-\udbff])([\udc00-\udfff]+)/g,
+    function (_, low, prefix, high) {
+      let output = prefix || '' // Prefix may be undefined
+      const string = low || high // Only one of these alternates can match
+      for (let i = 0; i < string.length; i++) {
+        output += codeUnitStr(string[i])
+      }
+      return output
+    })
+}
+
+function codeUnitStr (char) {
+  return 'U+' + char.charCodeAt(0).toString(16)
+}
+
 export class WPTRunner extends EventEmitter {
   /** @type {string} */
   #folderName
@@ -134,13 +153,29 @@ export class WPTRunner extends EventEmitter {
           }
         })
 
+        let result, report
+        if (WPT_REPORT) {
+          report = JSON.parse(readFileSync(WPT_REPORT))
+
+          const fileUrl = new URL(`/${this.#folderName}${test.slice(this.#folderPath.length)}`, 'http://wpt')
+          fileUrl.pathname = fileUrl.pathname.replace(/\.js$/, '.html')
+          fileUrl.search = variant
+
+          result = {
+            test: fileUrl.href.slice(fileUrl.origin.length),
+            subtests: [],
+            status: 'OK'
+          }
+          report.results.push(result)
+        }
+
         activeWorkers.add(worker)
         // These values come directly from the web-platform-tests
         const timeout = meta.timeout === 'long' ? 60_000 : 10_000
 
         worker.on('message', (message) => {
           if (message.type === 'result') {
-            this.handleIndividualTestCompletion(message, basename(test))
+            this.handleIndividualTestCompletion(message, basename(test), result)
           } else if (message.type === 'completion') {
             this.handleTestCompletion(worker)
           }
@@ -159,6 +194,10 @@ export class WPTRunner extends EventEmitter {
           console.log(`Test took ${(performance.now() - start).toFixed(2)}ms`)
           console.log('='.repeat(96))
 
+          if (result?.subtests.length > 0) {
+            writeFileSync(WPT_REPORT, JSON.stringify(report))
+          }
+
           finishedFiles++
         } catch (e) {
           console.log(`${test} timed out after ${timeout}ms`)
@@ -173,7 +212,7 @@ export class WPTRunner extends EventEmitter {
   /**
    * Called after a test has succeeded or failed.
    */
-  handleIndividualTestCompletion (message, fileName) {
+  handleIndividualTestCompletion (message, fileName, wptResult) {
     const { fail, allowUnexpectedFailures, flaky } = this.#status[fileName] ?? this.#status
 
     if (message.type === 'result') {
@@ -182,6 +221,12 @@ export class WPTRunner extends EventEmitter {
       if (message.result.status === 1) {
         this.#stats.failed += 1
 
+        wptResult?.subtests.push({
+          status: 'FAIL',
+          name: sanitizeUnpairedSurrogates(message.result.name),
+          message: sanitizeUnpairedSurrogates(message.result.message)
+        })
+
         const name = normalizeName(message.result.name)
 
         if (flaky?.includes(name)) {
@@ -197,6 +242,10 @@ export class WPTRunner extends EventEmitter {
           console.error(message.result)
         }
       } else {
+        wptResult?.subtests.push({
+          status: 'PASS',
+          name: sanitizeUnpairedSurrogates(message.result.name)
+        })
         this.#stats.success += 1
       }
     }