diff --git a/recipes/README.recipes.md b/recipes/README.recipes.md
index 141040eaf6..c924a6cc83 100644
--- a/recipes/README.recipes.md
+++ b/recipes/README.recipes.md
@@ -784,7 +784,7 @@ Raises:
 
 Returns a presubmit step.
 
-— **def [execute](/recipes/recipe_modules/presubmit/api.py#78)(self, bot_update_step, skip_owners=False):**
+— **def [execute](/recipes/recipe_modules/presubmit/api.py#100)(self, bot_update_step, skip_owners=False):**
 
 Runs presubmit and sets summary markdown if applicable.
 
@@ -795,7 +795,7 @@ Args:
 Returns:
   a RawResult object, suitable for being returned from RunSteps.
 
-— **def [prepare](/recipes/recipe_modules/presubmit/api.py#43)(self):**
+— **def [prepare](/recipes/recipe_modules/presubmit/api.py#65)(self):**
 
 Sets up a presubmit run.
 
diff --git a/recipes/recipe_modules/presubmit/api.py b/recipes/recipe_modules/presubmit/api.py
index a22dacbb56..05c0cb0708 100644
--- a/recipes/recipe_modules/presubmit/api.py
+++ b/recipes/recipe_modules/presubmit/api.py
@@ -38,7 +38,29 @@ class PresubmitApi(recipe_api.RecipeApi):
         kwargs['wrapper'] = ('rdb', 'stream', '--')
       step_data = self.m.python(
           name, self.presubmit_support_path, presubmit_args, **kwargs)
-      return step_data.json.output
+      output = step_data.json.output or {}
+      if self.m.step.active_result.retcode != 0:
+        return output
+
+      # Run with vpython3 directly
+      del (kwargs['venv'])
+      presubmit_args = list(args) + [
+          '--json_output',
+          self.m.json.output(),
+      ]
+      step_data = self.m.step(name + " py3",
+                              ['vpython3', self.presubmit_support_path] +
+                              presubmit_args, **kwargs)
+      output2 = step_data.json.output or {}
+
+      # combine outputs
+      for key in output:
+        if key in output2:
+          output[key] += output2[key]
+          del (output2[key])
+      for key in output2:
+        output[key] = output2[key]
+      return output
 
   def prepare(self):
     """Sets up a presubmit run.
diff --git a/recipes/recipe_modules/presubmit/examples/full.expected/basic.json b/recipes/recipe_modules/presubmit/examples/full.expected/basic.json
index f7a34181d8..8c0683b19c 100644
--- a/recipes/recipe_modules/presubmit/examples/full.expected/basic.json
+++ b/recipes/recipe_modules/presubmit/examples/full.expected/basic.json
@@ -21,6 +21,28 @@
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
+  {
+    "cmd": [
+      "vpython3",
+      "RECIPE_REPO[depot_tools]/presubmit_support.py",
+      "--json_output",
+      "/path/to/tmp/json"
+    ],
+    "env_suffixes": {
+      "DEPOT_TOOLS_UPDATE": [
+        "0"
+      ],
+      "PATH": [
+        "RECIPE_REPO[depot_tools]"
+      ]
+    },
+    "name": "presubmit py3",
+    "~followup_annotations": [
+      "@@@STEP_LOG_END@json.output (invalid)@@@",
+      "@@@STEP_LOG_LINE@json.output (exception)@No JSON object could be decoded@@@",
+      "@@@STEP_LOG_END@json.output (exception)@@@"
+    ]
+  },
   {
     "name": "$result"
   }
diff --git a/recipes/recipe_modules/presubmit/tests/execute.py b/recipes/recipe_modules/presubmit/tests/execute.py
index d65a610121..9af77b6430 100644
--- a/recipes/recipe_modules/presubmit/tests/execute.py
+++ b/recipes/recipe_modules/presubmit/tests/execute.py
@@ -121,6 +121,56 @@ def GenTests(api):
           Expected "," after item in list
           ```
 
+          #### To see notifications and warnings, look at the stdout of the presubmit step.
+        ''').strip()) + api.post_process(post_process.DropExpectation))
+  yield (
+      api.test('failure py3') + api.runtime(is_experimental=False) +
+      api.buildbucket.try_build(project='infra') + api.step_data(
+          'presubmit py3',
+          api.json.output(
+              {
+                  'errors': [{
+                      'message': 'Missing LGTM',
+                      'long_text': 'Here are some suggested OWNERS: fake@',
+                      'items': [],
+                      'fatal': True
+                  }, {
+                      'message': 'Syntax error in fake.py',
+                      'long_text': 'Expected "," after item in list',
+                      'items': [],
+                      'fatal': True
+                  }],
+                  'notifications': [{
+                      'message': 'If there is a bug associated please add it.',
+                      'long_text': '',
+                      'items': [],
+                      'fatal': False
+                  }],
+                  'warnings': [{
+                      'message': 'Line 100 has more than 80 characters',
+                      'long_text': '',
+                      'items': [],
+                      'fatal': False
+                  }]
+              },
+              retcode=1)) + api.post_process(post_process.StatusFailure) +
+      api.post_process(
+          post_process.ResultReason,
+          textwrap.dedent(u'''
+          #### There are 2 error(s), 1 warning(s), and 1 notifications(s). Here are the errors:
+
+          **ERROR**
+          ```
+          Missing LGTM
+          Here are some suggested OWNERS: fake@
+          ```
+
+          **ERROR**
+          ```
+          Syntax error in fake.py
+          Expected "," after item in list
+          ```
+
           #### To see notifications and warnings, look at the stdout of the presubmit step.
         ''').strip()) + api.post_process(post_process.DropExpectation))
 
@@ -213,3 +263,25 @@ def GenTests(api):
          api.post_process(post_process.StatusException) +
          api.post_process(post_process.ResultReason, bug_msg) +
          api.post_process(post_process.DropExpectation))
+
+  yield (api.test('warnings-merged') + api.runtime(is_experimental=False) +
+         api.buildbucket.try_build(project='infra') + api.step_data(
+             'presubmit',
+             api.json.output({
+                 'errors': [],
+                 'notifications': [],
+                 'warnings': [{
+                     'message': 'warning py2'
+                 }]
+             }),
+         ) + api.step_data(
+             'presubmit py3',
+             api.json.output({
+                 'errors': [],
+                 'extra': [],
+                 'warnings': [{
+                     'message': 'warning py3'
+                 }]
+             }),
+         ) + api.post_process(post_process.StatusSuccess) +
+         api.post_process(post_process.DropExpectation))