diff --git a/lighthouse-core/test/config/config-helpers-test.js b/lighthouse-core/test/config/config-helpers-test.js
index dd42fa7f9f11..7400e3582ad7 100644
--- a/lighthouse-core/test/config/config-helpers-test.js
+++ b/lighthouse-core/test/config/config-helpers-test.js
@@ -149,6 +149,11 @@ describe('.deepCloneConfigJson', () => {
 describe('.resolveSettings', () => {
   it('resolves the locale', () => {
     const settings = resolveSettings({locale: 'zh-CN'});
+    // COMPAT: Node 12 only has 'en' by default.
+    if (process.versions.node.startsWith('12')) {
+      expect(settings.locale).toEqual('en');
+      return;
+    }
     expect(settings.locale).toEqual('zh');
   });
 
diff --git a/lighthouse-core/test/config/config-test.js b/lighthouse-core/test/config/config-test.js
index a0f381ee5982..9f01267fa987 100644
--- a/lighthouse-core/test/config/config-test.js
+++ b/lighthouse-core/test/config/config-test.js
@@ -828,6 +828,8 @@ describe('Config', () => {
     it('uses config setting for locale if set', () => {
       const locale = 'ar-XB';
       const config = new Config({settings: {locale}});
+      // COMPAT: Node 12 only has 'en' by default.
+      if (process.versions.node.startsWith('12')) return;
       assert.strictEqual(config.settings.locale, locale);
     });
 
@@ -835,6 +837,8 @@ describe('Config', () => {
       const settingsLocale = 'en-XA';
       const flagsLocale = 'ar-XB';
       const config = new Config({settings: {locale: settingsLocale}}, {locale: flagsLocale});
+      // COMPAT: Node 12 only has 'en' by default.
+      if (process.versions.node.startsWith('12')) return;
       assert.strictEqual(config.settings.locale, flagsLocale);
     });
   });
diff --git a/lighthouse-core/test/lib/i18n/i18n-test.js b/lighthouse-core/test/lib/i18n/i18n-test.js
index dae823444c8f..cbb17f8a5b02 100644
--- a/lighthouse-core/test/lib/i18n/i18n-test.js
+++ b/lighthouse-core/test/lib/i18n/i18n-test.js
@@ -153,16 +153,34 @@ describe('i18n', () => {
 
     it('logs a warning if locale is not available and the default is used', () => {
       const logListener = jest.fn();
-      log.events.once('warning', logListener);
+      log.events.on('warning', logListener);
 
       expect(i18n.lookupLocale(invalidLocale)).toEqual('en');
 
+      // COMPAT: Node 12 logs an extra warning that full-icu is not available.
+      if (process.versions.node.startsWith('12')) {
+        expect(logListener).toBeCalledTimes(2);
+        expect(logListener).toHaveBeenNthCalledWith(1, ['i18n',
+          expect.stringMatching(/Requested locale not available in this version of node/)]);
+        expect(logListener).toHaveBeenNthCalledWith(2, ['i18n',
+          `locale(s) '${invalidLocale}' not available. Falling back to default 'en'`]);
+        return;
+      }
+
       expect(logListener).toBeCalledTimes(1);
       expect(logListener).toBeCalledWith(['i18n',
         `locale(s) '${invalidLocale}' not available. Falling back to default 'en'`]);
+
+      log.events.off('warning', logListener);
     });
 
     it('falls back to root tag prefix if specific locale not available', () => {
+      // COMPAT: Node 12 only has 'en' by default.
+      if (process.versions.node.startsWith('12')) {
+        expect(i18n.lookupLocale('es-JKJK')).toEqual('en');
+        return;
+      }
+
       expect(i18n.lookupLocale('es-JKJK')).toEqual('es');
     });
 
diff --git a/lighthouse-core/test/lib/i18n/swap-locale-test.js b/lighthouse-core/test/lib/i18n/swap-locale-test.js
index 6b6c2b0abc94..3c3b87dcf0e8 100644
--- a/lighthouse-core/test/lib/i18n/swap-locale-test.js
+++ b/lighthouse-core/test/lib/i18n/swap-locale-test.js
@@ -11,6 +11,25 @@ const lhr = require('../../results/sample_v2.json');
 
 /* eslint-env jest */
 describe('swap-locale', () => {
+  // COMPAT: Node 12 only has 'en' by default. Skip these tests since they're all about swapping locales.
+  if (process.versions.node.startsWith('12')) {
+    // Jest requires at least one test per suite.
+    it('runs even if other locales are not supported', () => {
+      /** @type {LH.Result} */
+      const lhrClone = JSON.parse(JSON.stringify(lhr));
+
+      // Even though 'pt' is requested, 'en' is all that's available.
+      const lhrEn = swapLocale(lhr, 'pt').lhr;
+      expect(lhrEn.configSettings.locale).toBe('en');
+
+      // Set locale back to full 'en-US' do do the comparison.
+      lhrEn.configSettings.locale = 'en-US';
+      expect(lhrEn).toStrictEqual(lhrClone);
+    });
+
+    return;
+  }
+
   it('does not mutate the original lhr', () => {
     /** @type {LH.Result} */
     const lhrClone = JSON.parse(JSON.stringify(lhr));
diff --git a/lighthouse-core/test/report/html/renderer/i18n-test.js b/lighthouse-core/test/report/html/renderer/i18n-test.js
index a204edbc267a..3921ca9cc767 100644
--- a/lighthouse-core/test/report/html/renderer/i18n-test.js
+++ b/lighthouse-core/test/report/html/renderer/i18n-test.js
@@ -106,6 +106,9 @@ describe('util helpers', () => {
   });
 
   it('formats numbers based on locale', () => {
+    // COMPAT: Node 12 only has 'en' by default.
+    if (process.versions.node.startsWith('12')) return;
+
     // Requires full-icu or Intl polyfill.
     const number = 12346.858558;
 
@@ -117,6 +120,9 @@ describe('util helpers', () => {
   });
 
   it('uses decimal comma with en-XA test locale', () => {
+    // COMPAT: Node 12 only has 'en' by default.
+    if (process.versions.node.startsWith('12')) return;
+
     // Requires full-icu or Intl polyfill.
     const number = 12346.858558;