diff --git a/.changeset/mean-forks-rest.md b/.changeset/mean-forks-rest.md
new file mode 100644
index 000000000..5812d4a71
--- /dev/null
+++ b/.changeset/mean-forks-rest.md
@@ -0,0 +1,6 @@
+---
+"@web/test-runner-mocha": patch
+"@web/test-runner": patch
+---
+
+Use full path to browser session file
diff --git a/packages/test-runner-mocha/rollup.config.js b/packages/test-runner-mocha/rollup.config.js
index 809e3b56e..8db9c72c8 100644
--- a/packages/test-runner-mocha/rollup.config.js
+++ b/packages/test-runner-mocha/rollup.config.js
@@ -10,7 +10,7 @@ const rewriteDtsPlugin = {
       if (name.endsWith('.d.ts')) {
         file.source = file.source
           .replace(REGEXP_DTS_MOCHA, "'mocha/mocha.js'")
-          .replace(REGEXP_DTS_CORE, "'@web/test-runner-core'");
+          .replace(REGEXP_DTS_CORE, "'@web/test-runner-core/browser/session.js'");
       }
     }
   },