diff --git a/CHANGELOG.md b/CHANGELOG.md
index 51248fd473..dbd1e20772 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -53,6 +53,7 @@
 - Add experimental version of `init` with optional `OptionsConfiguration<SentryAndroidOptions>` for Android ([#4451](https://github.com/getsentry/sentry-react-native/pull/4451))
 - Add initialization using `sentry.options.json` for Apple platforms ([#4447](https://github.com/getsentry/sentry-react-native/pull/4447))
 - Add initialization using `sentry.options.json` for Android ([#4451](https://github.com/getsentry/sentry-react-native/pull/4451))
+- Merge options from file with `Sentry.init` options in JS ([#4510](https://github.com/getsentry/sentry-react-native/pull/4510))
 
 ### Internal
 
diff --git a/packages/core/src/js/sdk.tsx b/packages/core/src/js/sdk.tsx
index 3c6fdff90c..3ff40508af 100644
--- a/packages/core/src/js/sdk.tsx
+++ b/packages/core/src/js/sdk.tsx
@@ -19,6 +19,7 @@ import { useEncodePolyfill } from './transports/encodePolyfill';
 import { DEFAULT_BUFFER_SIZE, makeNativeTransportFactory } from './transports/native';
 import { getDefaultEnvironment, isExpoGo, isRunningInMetroDevServer } from './utils/environment';
 import { safeFactory, safeTracesSampler } from './utils/safe';
+import { RN_GLOBAL_OBJ } from './utils/worldwide';
 import { NATIVE } from './wrapper';
 
 const DEFAULT_OPTIONS: ReactNativeOptions = {
@@ -47,12 +48,17 @@ export function init(passedOptions: ReactNativeOptions): void {
     return;
   }
 
-  const maxQueueSize = passedOptions.maxQueueSize
+  const userOptions = {
+    ...RN_GLOBAL_OBJ.__SENTRY_OPTIONS__,
+    ...passedOptions,
+  };
+
+  const maxQueueSize = userOptions.maxQueueSize
     // eslint-disable-next-line deprecation/deprecation
-    ?? passedOptions.transportOptions?.bufferSize
+    ?? userOptions.transportOptions?.bufferSize
     ?? DEFAULT_OPTIONS.maxQueueSize;
 
-  const enableNative = passedOptions.enableNative === undefined || passedOptions.enableNative
+  const enableNative = userOptions.enableNative === undefined || userOptions.enableNative
     ? NATIVE.isNativeAvailable()
     : false;
 
@@ -75,11 +81,11 @@ export function init(passedOptions: ReactNativeOptions): void {
     return `${dsnComponents.protocol}://${dsnComponents.host}${port}`;
   };
 
-  const userBeforeBreadcrumb = safeFactory(passedOptions.beforeBreadcrumb, { loggerMessage: 'The beforeBreadcrumb threw an error' });
+  const userBeforeBreadcrumb = safeFactory(userOptions.beforeBreadcrumb, { loggerMessage: 'The beforeBreadcrumb threw an error' });
 
   // Exclude Dev Server and Sentry Dsn request from Breadcrumbs
   const devServerUrl = getDevServer()?.url;
-  const dsn = getURLFromDSN(passedOptions.dsn);
+  const dsn = getURLFromDSN(userOptions.dsn);
   const defaultBeforeBreadcrumb = (breadcrumb: Breadcrumb, _hint?: BreadcrumbHint): Breadcrumb | null => {
     const type = breadcrumb.type || '';
     const url = typeof breadcrumb.data?.url === 'string' ? breadcrumb.data.url : '';
@@ -103,26 +109,34 @@ export function init(passedOptions: ReactNativeOptions): void {
 
   const options: ReactNativeClientOptions = {
     ...DEFAULT_OPTIONS,
-    ...passedOptions,
+    ...userOptions,
     enableNative,
-    enableNativeNagger: shouldEnableNativeNagger(passedOptions.enableNativeNagger),
+    enableNativeNagger: shouldEnableNativeNagger(userOptions.enableNativeNagger),
     // If custom transport factory fails the SDK won't initialize
-    transport: passedOptions.transport
+    transport: userOptions.transport
       || makeNativeTransportFactory({
         enableNative,
       })
       || makeFetchTransport,
     transportOptions: {
       ...DEFAULT_OPTIONS.transportOptions,
-      ...(passedOptions.transportOptions ?? {}),
+      ...(userOptions.transportOptions ?? {}),
       bufferSize: maxQueueSize,
     },
     maxQueueSize,
     integrations: [],
-    stackParser: stackParserFromStackParserOptions(passedOptions.stackParser || defaultStackParser),
+    stackParser: stackParserFromStackParserOptions(userOptions.stackParser || defaultStackParser),
     beforeBreadcrumb: chainedBeforeBreadcrumb,
-    initialScope: safeFactory(passedOptions.initialScope, { loggerMessage: 'The initialScope threw an error' }),
+    initialScope: safeFactory(userOptions.initialScope, { loggerMessage: 'The initialScope threw an error' }),
   };
+
+  if (!('autoInitializeNativeSdk' in userOptions) && RN_GLOBAL_OBJ.__SENTRY_OPTIONS__) {
+    // We expect users to use the file options only in combination with manual native initialization
+    // eslint-disable-next-line no-console
+    console.info('Initializing Sentry JS with the options file. Expecting manual native initialization before JS. Native will not be initialized automatically.');
+    options.autoInitializeNativeSdk = false;
+  }
+
   if ('tracesSampler' in options) {
     options.tracesSampler = safeTracesSampler(options.tracesSampler);
   }
@@ -131,12 +145,12 @@ export function init(passedOptions: ReactNativeOptions): void {
     options.environment = getDefaultEnvironment();
   }
 
-  const defaultIntegrations: false | Integration[] = passedOptions.defaultIntegrations === undefined
+  const defaultIntegrations: false | Integration[] = userOptions.defaultIntegrations === undefined
     ? getDefaultIntegrations(options)
-    : passedOptions.defaultIntegrations;
+    : userOptions.defaultIntegrations;
 
   options.integrations = getIntegrationsToSetup({
-    integrations: safeFactory(passedOptions.integrations, { loggerMessage: 'The integrations threw an error' }),
+    integrations: safeFactory(userOptions.integrations, { loggerMessage: 'The integrations threw an error' }),
     defaultIntegrations,
   });
   initAndBind(ReactNativeClient, options);
@@ -145,6 +159,10 @@ export function init(passedOptions: ReactNativeOptions): void {
     logger.info('Offline caching, native errors features are not available in Expo Go.');
     logger.info('Use EAS Build / Native Release Build to test these features.');
   }
+
+  if (RN_GLOBAL_OBJ.__SENTRY_OPTIONS__) {
+    logger.info('Sentry JS initialized with options from the options file.');
+  }
 }
 
 /**
diff --git a/packages/core/src/js/utils/worldwide.ts b/packages/core/src/js/utils/worldwide.ts
index c1a4ae5dbb..0dc265763d 100644
--- a/packages/core/src/js/utils/worldwide.ts
+++ b/packages/core/src/js/utils/worldwide.ts
@@ -2,6 +2,7 @@ import type { InternalGlobal } from '@sentry/core';
 import { GLOBAL_OBJ } from '@sentry/core';
 import type { ErrorUtils } from 'react-native/types';
 
+import type { ReactNativeOptions } from '../options';
 import type { ExpoGlobalObject } from './expoglobalobject';
 
 /** Internal Global object interface with common and Sentry specific properties */
@@ -25,6 +26,7 @@ export interface ReactNativeInternalGlobal extends InternalGlobal {
   __BUNDLE_START_TIME__?: number;
   nativePerformanceNow?: () => number;
   TextEncoder?: TextEncoder;
+  __SENTRY_OPTIONS__?: ReactNativeOptions;
 }
 
 type TextEncoder = {
diff --git a/packages/core/test/sdk.test.ts b/packages/core/test/sdk.test.ts
index afd6137c8a..0e64264899 100644
--- a/packages/core/test/sdk.test.ts
+++ b/packages/core/test/sdk.test.ts
@@ -1,13 +1,15 @@
-import type { BaseTransportOptions, Breadcrumb, BreadcrumbHint, ClientOptions, Integration, Scope } from '@sentry/core';
+import type { Breadcrumb, BreadcrumbHint, Integration, Scope } from '@sentry/core';
 import { initAndBind, logger } from '@sentry/core';
 import { makeFetchTransport } from '@sentry/react';
 
 import { getDevServer } from '../src/js/integrations/debugsymbolicatorutils';
+import type { ReactNativeClientOptions } from '../src/js/options';
 import { init, withScope } from '../src/js/sdk';
 import type { ReactNativeTracingIntegration } from '../src/js/tracing';
 import { REACT_NATIVE_TRACING_INTEGRATION_NAME, reactNativeTracingIntegration } from '../src/js/tracing';
 import { makeNativeTransport } from '../src/js/transports/native';
 import { getDefaultEnvironment, isExpoGo, notWeb } from '../src/js/utils/environment';
+import { RN_GLOBAL_OBJ } from '../src/js/utils/worldwide';
 import { NATIVE } from './mockWrapper';
 import { firstArg, secondArg } from './testutils';
 
@@ -109,6 +111,60 @@ describe('Tests the SDK functionality', () => {
       });
     });
 
+    describe('initialization from sentry.options.json', () => {
+      it('initializes without __SENTRY_OPTIONS__', () => {
+        delete RN_GLOBAL_OBJ.__SENTRY_OPTIONS__;
+        init({});
+        expect(initAndBind).toHaveBeenCalledOnce();
+      });
+
+      it('adds options from __SENTRY_OPTIONS__', () => {
+        RN_GLOBAL_OBJ.__SENTRY_OPTIONS__ = {
+          dsn: 'https://key@example.io/value',
+        };
+        init({});
+        expect(usedOptions()?.dsn).toBe('https://key@example.io/value');
+      });
+
+      it('options init override options from __SENTRY_OPTIONS__', () => {
+        RN_GLOBAL_OBJ.__SENTRY_OPTIONS__ = {
+          dsn: 'https://key@example.io/file',
+        };
+        init({
+          dsn: 'https://key@example.io/code',
+        });
+        expect(usedOptions()?.dsn).toBe('https://key@example.io/code');
+      });
+
+      it('initializing with __SENTRY_OPTIONS__ disabled native auto initialization', () => {
+        RN_GLOBAL_OBJ.__SENTRY_OPTIONS__ = {};
+        init({});
+        expect(usedOptions()?.autoInitializeNativeSdk).toBe(false);
+      });
+
+      it('initializing without __SENTRY_OPTIONS__ enables native auto initialization', () => {
+        RN_GLOBAL_OBJ.__SENTRY_OPTIONS__ = undefined;
+        init({});
+        expect(usedOptions()?.autoInitializeNativeSdk).toBe(true);
+      });
+
+      it('initializing with __SENTRY_OPTIONS__ keeps native auto initialization true if set', () => {
+        RN_GLOBAL_OBJ.__SENTRY_OPTIONS__ = {};
+        init({
+          autoInitializeNativeSdk: true,
+        });
+        expect(usedOptions()?.autoInitializeNativeSdk).toBe(true);
+      });
+
+      it('initializing with __SENTRY_OPTIONS__ keeps native auto initialization false if set', () => {
+        RN_GLOBAL_OBJ.__SENTRY_OPTIONS__ = {};
+        init({
+          autoInitializeNativeSdk: false,
+        });
+        expect(usedOptions()?.autoInitializeNativeSdk).toBe(false);
+      });
+    });
+
     describe('environment', () => {
       it('detect development environment', () => {
         (getDefaultEnvironment as jest.Mock).mockImplementation(() => 'development');
@@ -173,7 +229,6 @@ describe('Tests the SDK functionality', () => {
         (NATIVE.isNativeAvailable as jest.Mock).mockImplementation(() => false);
         init({});
         expect(NATIVE.isNativeAvailable).toBeCalled();
-        // @ts-expect-error enableNative not publicly available here.
         expect(usedOptions()?.enableNative).toEqual(false);
         expect(usedOptions()?.transport).toEqual(makeFetchTransport);
       });
@@ -182,7 +237,6 @@ describe('Tests the SDK functionality', () => {
         (NATIVE.isNativeAvailable as jest.Mock).mockImplementation(() => false);
         init({ enableNative: true });
         expect(NATIVE.isNativeAvailable).toBeCalled();
-        // @ts-expect-error enableNative not publicly available here.
         expect(usedOptions()?.enableNative).toEqual(false);
         expect(usedOptions()?.transport).toEqual(makeFetchTransport);
       });
@@ -191,7 +245,6 @@ describe('Tests the SDK functionality', () => {
         (NATIVE.isNativeAvailable as jest.Mock).mockImplementation(() => false);
         init({ enableNative: false });
         expect(NATIVE.isNativeAvailable).not.toBeCalled();
-        // @ts-expect-error enableNative not publicly available here.
         expect(usedOptions()?.enableNative).toEqual(false);
         expect(usedOptions()?.transport).toEqual(makeFetchTransport);
       });
@@ -204,7 +257,6 @@ describe('Tests the SDK functionality', () => {
         });
         expect(usedOptions()?.transport).toEqual(mockTransport);
         expect(NATIVE.isNativeAvailable).toBeCalled();
-        // @ts-expect-error enableNative not publicly available here.
         expect(usedOptions()?.enableNative).toEqual(false);
       });
     });
@@ -1058,7 +1110,7 @@ function createMockedIntegration({ name }: { name?: string } = {}): Integration
   };
 }
 
-function usedOptions(): ClientOptions<BaseTransportOptions> | undefined {
+function usedOptions(): ReactNativeClientOptions | undefined {
   return (initAndBind as jest.MockedFunction<typeof initAndBind>).mock.calls[0]?.[secondArg];
 }