diff --git a/readthedocs/projects/migrations/0165_external_builds_enabled_default_true.py b/readthedocs/projects/migrations/0165_external_builds_enabled_default_true.py
new file mode 100644
index 00000000000..761698eca87
--- /dev/null
+++ b/readthedocs/projects/migrations/0165_external_builds_enabled_default_true.py
@@ -0,0 +1,34 @@
+# Generated by Django 5.2.12 on 2026-05-12
+
+from django.db import migrations
+from django.db import models
+from django_safemigrate import Safe
+
+
+class Migration(migrations.Migration):
+    safe = Safe.before_deploy()
+
+    dependencies = [
+        ("projects", "0164_show_build_overview_in_comment_default_true"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="historicalproject",
+            name="external_builds_enabled",
+            field=models.BooleanField(
+                default=True,
+                help_text='More information in <a href="https://docs.readthedocs.io/page/guides/autobuild-docs-for-pull-requests.html">our docs</a>.',
+                verbose_name="Build pull requests for this project",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="project",
+            name="external_builds_enabled",
+            field=models.BooleanField(
+                default=True,
+                help_text='More information in <a href="https://docs.readthedocs.io/page/guides/autobuild-docs-for-pull-requests.html">our docs</a>.',
+                verbose_name="Build pull requests for this project",
+            ),
+        ),
+    ]
diff --git a/readthedocs/projects/models.py b/readthedocs/projects/models.py
index 28e28194710..cff0a306810 100644
--- a/readthedocs/projects/models.py
+++ b/readthedocs/projects/models.py
@@ -426,7 +426,7 @@ class Project(models.Model):
     # External versions
     external_builds_enabled = models.BooleanField(
         _("Build pull requests for this project"),
-        default=False,
+        default=True,
         help_text=_(
             'More information in <a href="https://docs.readthedocs.io/page/guides/autobuild-docs-for-pull-requests.html">our docs</a>.'  # noqa
         ),