diff --git a/.changeset/satellite-auto-sync-codemod.md b/.changeset/satellite-auto-sync-codemod.md
new file mode 100644
index 00000000000..c87902fe554
--- /dev/null
+++ b/.changeset/satellite-auto-sync-codemod.md
@@ -0,0 +1,5 @@
+---
+'@clerk/upgrade': minor
+---
+
+Add `transform-satellite-auto-sync` codemod for Core 3 migration that adds `satelliteAutoSync: true` wherever `isSatellite` is configured
diff --git a/packages/upgrade/src/codemods/__tests__/__fixtures__/transform-satellite-auto-sync.fixtures.js b/packages/upgrade/src/codemods/__tests__/__fixtures__/transform-satellite-auto-sync.fixtures.js
new file mode 100644
index 00000000000..88343606e85
--- /dev/null
+++ b/packages/upgrade/src/codemods/__tests__/__fixtures__/transform-satellite-auto-sync.fixtures.js
@@ -0,0 +1,173 @@
+export const fixtures = [
+  {
+    name: 'JSX: isSatellite={true}',
+    source: `
+import { ClerkProvider } from '@clerk/nextjs';
+
+export function App({ children }) {
+  return (
+    <ClerkProvider isSatellite={true} domain="example.com">
+      {children}
+    </ClerkProvider>
+  );
+}
+    `,
+    output: `
+import { ClerkProvider } from '@clerk/nextjs';
+
+export function App({ children }) {
+  return (
+    <ClerkProvider isSatellite={true} domain="example.com" satelliteAutoSync={true}>
+      {children}
+    </ClerkProvider>
+  );
+}
+    `,
+  },
+  {
+    name: 'JSX: isSatellite (boolean shorthand)',
+    source: `
+import { ClerkProvider } from '@clerk/react';
+
+export const App = () => (
+  <ClerkProvider isSatellite domain="satellite.example.com">
+    <Main />
+  </ClerkProvider>
+);
+    `,
+    output: `
+import { ClerkProvider } from '@clerk/react';
+
+export const App = () => (
+  <ClerkProvider isSatellite domain="satellite.example.com" satelliteAutoSync={true}>
+    <Main />
+  </ClerkProvider>
+);
+    `,
+  },
+  {
+    name: 'JSX: isSatellite with function value',
+    source: `
+import { ClerkProvider } from '@clerk/nextjs';
+
+export function App({ children }) {
+  return (
+    <ClerkProvider isSatellite={(url) => url.host === 'satellite.example.com'} domain="example.com">
+      {children}
+    </ClerkProvider>
+  );
+}
+    `,
+    output: `
+import { ClerkProvider } from '@clerk/nextjs';
+
+export function App({ children }) {
+  return (
+    <ClerkProvider
+      isSatellite={(url) => url.host === 'satellite.example.com'}
+      domain="example.com"
+      satelliteAutoSync={true}>
+      {children}
+    </ClerkProvider>
+  );
+}
+    `,
+  },
+  {
+    name: 'JSX: already has satelliteAutoSync',
+    source: `
+import { ClerkProvider } from '@clerk/nextjs';
+
+export function App({ children }) {
+  return (
+    <ClerkProvider isSatellite={true} satelliteAutoSync={false} domain="example.com">
+      {children}
+    </ClerkProvider>
+  );
+}
+    `,
+    noChange: true,
+  },
+  {
+    name: 'Object: isSatellite in clerkMiddleware options',
+    source: `
+import { clerkMiddleware } from '@clerk/nextjs/server';
+
+export default clerkMiddleware({
+  isSatellite: true,
+  domain: 'example.com',
+});
+    `,
+    output: `
+import { clerkMiddleware } from '@clerk/nextjs/server';
+
+export default clerkMiddleware({
+  isSatellite: true,
+  satelliteAutoSync: true,
+  domain: 'example.com'
+});
+    `,
+  },
+  {
+    name: 'Object: isSatellite in variable declaration',
+    source: `
+const options = {
+  isSatellite: true,
+  domain: 'satellite.example.com',
+};
+    `,
+    output: `
+const options = {
+  isSatellite: true,
+  satelliteAutoSync: true,
+  domain: 'satellite.example.com'
+};
+    `,
+  },
+  {
+    name: 'Object: isSatellite with function value',
+    source: `
+import { clerkMiddleware } from '@clerk/nextjs/server';
+
+export default clerkMiddleware({
+  isSatellite: (url) => url.host === 'satellite.example.com',
+  domain: 'example.com',
+});
+    `,
+    output: `
+import { clerkMiddleware } from '@clerk/nextjs/server';
+
+export default clerkMiddleware({
+  isSatellite: (url) => url.host === 'satellite.example.com',
+  satelliteAutoSync: true,
+  domain: 'example.com'
+});
+    `,
+  },
+  {
+    name: 'Object: already has satelliteAutoSync',
+    source: `
+const options = {
+  isSatellite: true,
+  satelliteAutoSync: false,
+  domain: 'example.com',
+};
+    `,
+    noChange: true,
+  },
+  {
+    name: 'No isSatellite present (no changes)',
+    source: `
+import { ClerkProvider } from '@clerk/nextjs';
+
+export function App({ children }) {
+  return (
+    <ClerkProvider domain="example.com">
+      {children}
+    </ClerkProvider>
+  );
+}
+    `,
+    noChange: true,
+  },
+];
diff --git a/packages/upgrade/src/codemods/__tests__/transform-satellite-auto-sync.test.js b/packages/upgrade/src/codemods/__tests__/transform-satellite-auto-sync.test.js
new file mode 100644
index 00000000000..a9be8e56e98
--- /dev/null
+++ b/packages/upgrade/src/codemods/__tests__/transform-satellite-auto-sync.test.js
@@ -0,0 +1,17 @@
+import { applyTransform } from 'jscodeshift/dist/testUtils';
+import { describe, expect, it } from 'vitest';
+
+import transformer from '../transform-satellite-auto-sync.cjs';
+import { fixtures } from './__fixtures__/transform-satellite-auto-sync.fixtures';
+
+describe('transform-satellite-auto-sync', () => {
+  it.each(fixtures)('$name', ({ source, output, noChange }) => {
+    const result = applyTransform(transformer, {}, { source });
+
+    if (noChange) {
+      expect(result).toEqual('');
+    } else {
+      expect(result).toEqual(output.trim());
+    }
+  });
+});
diff --git a/packages/upgrade/src/codemods/transform-satellite-auto-sync.cjs b/packages/upgrade/src/codemods/transform-satellite-auto-sync.cjs
new file mode 100644
index 00000000000..4deb5506cd4
--- /dev/null
+++ b/packages/upgrade/src/codemods/transform-satellite-auto-sync.cjs
@@ -0,0 +1,74 @@
+module.exports = function transformSatelliteAutoSync({ source }, { jscodeshift: j }) {
+  const root = j(source);
+  let dirty = false;
+
+  // Handle JSX attributes: <Component isSatellite /> → <Component isSatellite satelliteAutoSync={true} />
+  root.find(j.JSXOpeningElement).forEach(path => {
+    const { attributes } = path.node;
+    if (!attributes) {
+      return;
+    }
+
+    const hasIsSatellite = attributes.some(attr => isJsxAttrNamed(attr, 'isSatellite'));
+    if (!hasIsSatellite) {
+      return;
+    }
+
+    const hasAutoSync = attributes.some(attr => isJsxAttrNamed(attr, 'satelliteAutoSync'));
+    if (hasAutoSync) {
+      return;
+    }
+
+    const autoSyncAttr = j.jsxAttribute(
+      j.jsxIdentifier('satelliteAutoSync'),
+      j.jsxExpressionContainer(j.booleanLiteral(true)),
+    );
+    attributes.push(autoSyncAttr);
+    dirty = true;
+  });
+
+  // Handle object properties: { isSatellite: true } → { isSatellite: true, satelliteAutoSync: true }
+  root.find(j.ObjectExpression).forEach(path => {
+    const { properties } = path.node;
+
+    const hasIsSatellite = properties.some(prop => isObjectPropertyNamed(prop, 'isSatellite'));
+    if (!hasIsSatellite) {
+      return;
+    }
+
+    const hasAutoSync = properties.some(prop => isObjectPropertyNamed(prop, 'satelliteAutoSync'));
+    if (hasAutoSync) {
+      return;
+    }
+
+    const isSatelliteIndex = properties.findIndex(prop => isObjectPropertyNamed(prop, 'isSatellite'));
+    const autoSyncProp = j.objectProperty(j.identifier('satelliteAutoSync'), j.booleanLiteral(true));
+    properties.splice(isSatelliteIndex + 1, 0, autoSyncProp);
+    dirty = true;
+  });
+
+  return dirty ? root.toSource() : undefined;
+};
+
+module.exports.parser = 'tsx';
+
+function isJsxAttrNamed(attribute, name) {
+  return attribute && attribute.type === 'JSXAttribute' && attribute.name && attribute.name.name === name;
+}
+
+function isObjectPropertyNamed(prop, name) {
+  if (!prop || (prop.type !== 'ObjectProperty' && prop.type !== 'Property')) {
+    return false;
+  }
+  const { key } = prop;
+  if (!key) {
+    return false;
+  }
+  if (key.type === 'Identifier') {
+    return key.name === name;
+  }
+  if (key.type === 'StringLiteral' || key.type === 'Literal') {
+    return key.value === name;
+  }
+  return false;
+}
diff --git a/packages/upgrade/src/versions/core-3/index.js b/packages/upgrade/src/versions/core-3/index.js
index 2a22f7640c5..ab4ba699da5 100644
--- a/packages/upgrade/src/versions/core-3/index.js
+++ b/packages/upgrade/src/versions/core-3/index.js
@@ -29,5 +29,6 @@ export default {
     { name: 'transform-clerk-provider-inside-body', packages: ['nextjs'] },
     // Migrate @clerk/react-router/api.server → @clerk/react-router/server
     { name: 'transform-react-router-api-server', packages: ['react-router'] },
+    { name: 'transform-satellite-auto-sync', packages: ['nextjs', 'react', 'expo', 'astro', 'tanstack-react-start'] },
   ],
 };