Have you ever landed in another country, pulled out your phone to call home, and suddenly realized your “smartphone” is only good for taking pictures? You try your usual app, but it only works if the person on the other end has it too. So you wait for Wi-Fi, switch apps, and still get that annoying “call failed” pop-up. It’s one of those frustrating travel moments no one prepares you for. And that’s when you start searching for the best international calling app. One that actually lets you call anyone, anywhere, without jumping through hoops. But here’s the thing: most “free” calling apps aren’t truly global. They sound great on paper, but they usually work only between users of the same app. If your mom or business contact doesn’t have it, tough luck.

So, in this guide, we’re cutting through the noise. You’ll find the 10 best calling apps for Android and iPhone, how each one works, and which one truly lets you connect beyond borders, no matter where you are or who you’re calling.

Why International Calling Apps Matter More Than Ever

Let’s be honest, traditional roaming feels outdated. Those sky-high charges can turn a quick “Hi Mom” into a $20 surprise on your next bill. And SIM cards? They’re a headache when you’re traveling through multiple countries. This is why global calling apps have taken over. They use Wi-Fi or mobile data to let you make calls at little to no cost. You can chat, video call, or even send mobile balance without touching your carrier minutes. But the problem isn’t finding an app. It’s finding one that actually works everywhere, not just between users of the same app. That’s where things get tricky. So, let’s explore which apps people actually use, what they do well, and where they fall short. 

10 Best International Calling Apps for Android & iPhone

Here’s a practical look at the top apps millions rely on to stay in touch around the world.

1. Slick – The All-in-One International Calling App

If you want one app that simplifies everything, international calls, mobile recharge, and affordable data eSIMs, Slick is built exactly for that. It’s not just another app; it’s designed for real-world connectivity.

Why people love Slick:

• Free Slick-to-Slick calls: Make free Slick-to-Slick calls with end-to-end encryption.
• Call landlines & mobiles: Make calls to any mobile or landline number in 200+ countries.
• Call offline numbers: Make calls even to offline numbers.
• No app required: Call anyone who doesn’t even have the Slick app.
• Instant recharge: Send mobile recharge in seconds without hidden fees.
• Affordable calling plans: Subscribe to low-cost international calling plans starting from as low as $2 per month.
• Clear calls: Make crystal-clear calls worldwide, even with slow internet.
• Global data eSIMs: Buy data eSIM plans for 150+ countries.
• Secure payments: Slick ensures secure payments and a clean, easy-to-use interface.

Most calling apps stop at “free.” Slick goes beyond. It lets you reach anyone. Even if they don’t have the app installed. Whether you’re calling family in the Philippines, clients in Canada, or friends in Germany, Slick keeps it seamless. And the best part? Calls are optimized for stable, high-quality sound. No awkward delays or distorted voices, even on weak networks.

If you’ve ever wished for one app that just works anywhere, Slick is your answer.

2. WhatsApp

Let’s be real, almost everyone has WhatsApp. It’s free, familiar, and works across platforms.

What’s good:

• Free voice and video calls between WhatsApp users
• End-to-end encryption
• Works smoothly on Wi-Fi or mobile data

What’s not so good:

• Only works if both people have WhatsApp
• No way to call landlines or regular mobile numbers

So while WhatsApp is an essential tool for chatting and sharing updates, it doesn’t work as a full global calling app when you need to reach someone offline or outside the app world.

3. Viber

Viber is another popular app that feels like WhatsApp’s older, more versatile cousin. It’s been around for ages and offers great quality calls.

Pros:

• Free app-to-app calls
• Excellent voice clarity
• End-to-end encryption
• “Viber Out” option for calling external numbers

Cons:

• You’ll need to pay to call landlines or non-Viber users
• Rates can vary depending on the country

Viber is handy if most of your circle uses it, but when it comes to calling random or new numbers abroad, those small fees can start adding up.

4. Google Voice

Google Voice gives you a free number that works across devices for calls, messages, and voicemail. It’s particularly convenient for US residents.

Pros:

• Free calls within the US and Canada
• Reasonable international rates
• Works across Android, iOS, and desktops

Cons:

• Mostly limited to US-based users
• Not ideal for global travelers

Google Voice is dependable but not fully global. It’s a solid option for the US users but less practical if you’re hopping between time zones or continents.

5. FaceTime

Apple users adore FaceTime for its smooth video and audio quality. It’s intuitive, integrated, and feels effortless.

Pros:

• Built into every Apple device
• HD audio and video quality
• Easy one-tap connection

Cons:

• Only works between Apple devices
• No Android or landline support

FaceTime is like an exclusive club. It’s beautiful inside, but you can’t invite everyone. If you’re calling across platforms, you’ll need an alternative calling app.

6. LINE

LINE is huge in Japan, Taiwan, and Thailand. It’s part messenger, part social app, and part calling app.

Pros:

• Free app-to-app calls
• Fun stickers, themes, and mini-games
• LINE Out feature for non-user calls

Cons:

• Not very popular outside Asia
• Uses more data compared to lighter apps

7. WeChat

If you’re in China, WeChat is impossible to avoid. It combines chat, payments, social media, and calling in one platform.

Pros:

• Free voice and video calls
• Payment and social features in one app
• Strong local reliability

Cons:

• Limited global functionality
• Restricted outside China

WeChat is ideal for communication within China, but you will quickly run into problems if you try to use it outside China.

8. Telegram 

Telegram is renowned for its speed and security.  It is rapidly expanding among consumers who value dependability and privacy.

Pros:

• Secure calls with strong encryption
• Lightweight and fast
• Works well even on weak connections

Cons:

• App-to-app only
• No landline or external calling

Telegram is a fantastic messaging app, but because it can’t call numbers outside of the app, it’s still not a full app for global calling.

9. Facebook Messenger 

The strength of Messenger is its broad use. If both of you have the internet, calling is simple because almost everyone has Facebook.

Pros:

• Free calls and video chats
• Built into Facebook
• Works across devices

Cons:

• Needs a strong internet connection
• Can consume a lot of battery and data
• It’s great for casual chats but not reliable for professional or offline communication.

10. Signal 

Signal’s emphasis on anonymity makes it popular.  It is open source, safe, and simple.

Pros:

• End-to-end encryption
• Simple, distraction-free design
• Free app-to-app calls

Cons:

• No calls to external numbers
• Small user base compared to others

Signal is ideal for those who value anonymity, but it isn’t a complete international calling tool that can be used to contact anybody, anywhere.

Why Most Global Calling Apps Still Fall Short

You’ve probably noticed the pattern: most of these apps only let you call someone who uses the same app. That’s the biggest limitation. Here’s what usually goes wrong:

• You can’t call landlines or non-users.
• You can’t reach offline numbers.
• Call quality drops with weak internet.
• Hidden fees pop up for “premium” calls.
• Regional restrictions block usage in some countries.
• You end up switching between apps to reach different people.
• If you’re juggling five apps just to stay connected, it’s not convenient; it’s chaos.

This is where Slick stands apart. It doesn’t just help you talk to app users; it helps you reach anyone who owns a phone.

Why Slick Stands Out as the Best International Calling App for Android and iPhone

Slick was built for modern travelers, expats, and anyone who wants to stay connected without limits. It is easy to use, quick, and dependable. There are no complex setup requirements or “only if they have the app” restrictions.

Let’s break down why Slick leads the pack.

1. Call Mobiles & Landlines – Reach Offline Numbers Too

In more than 200 countries, you can call landlines, mobile phones, and users who don’t use the Slick app. No extra apps, no internet on the receiver’s side required. That makes it a truly global international calling app.

Imagine being able to use a single platform to call your employer who works overseas, your kids who live far away, or your grandmother who lives in a tiny town. Slick really brings that kind of flexibility to the table.

2. Free and Affordable Together

Slick’s biggest strength is balance. You get free Slick-to-Slick calls, and if you want to go beyond, you can subscribe to affordable calling plans. Plans start as low as $2 per month, making international communication cheaper than a cup of coffee. It’s ideal for long-distance families, frequent travelers, and even small business owners.

3. Clear, Secure Calls You Can Trust

There’s really not much that’s more frustrating than a call that’s all muffled and lagging. Slick keeps things clear and smooth, even if your internet connection isn’t the best. 

All your calls are encrypted, so you can chat away knowing your conversations are private and secure. You’ll enjoy the clear connection of a local call, plus the peace of mind that comes with a top-notch service.

4. Global Calling, Recharge, Data in 1 App

All you need is right there in one smooth app. International calling, mobile recharge, and data eSIMs. Recharge in a snap, sign up for plans, or make secure payments with just a few taps. You don’t have to switch between different apps. It’s all about making things easy for you.

5. Coverage That Matches Your Lifestyle

Slick’s got your back in over 200 countries, so you can stay connected wherever you go. No matter if you’re a student in Canada, a business traveler in Europe, or a family member living overseas, Slick is here to fit your needs.

6. Instant Installation on Android and iPhone

Whether you’re using an Android or an iPhone, you can easily install and use the Slick app. Without any lag, you can not only make international calls but also buy data eSIMs and send mobile recharges.  The Slick app is fully compatible with all Android and iPhone models, and you can install it from the Google Play Store or App Store within seconds.

7. Your Account, Double-Verified and Fully Secure

When it comes to login and account security, Slick treats it as a top priority. After installing the app, you register using your phone number. For extra security, you receive a one-time password (OTP) that you enter to complete your sign-up. To make the process smoother, Slick lets you choose how you’d like to receive the OTP—via SMS or WhatsApp. 

Bottom line

Most popular apps are great for chatting within the same ecosystem. WhatsApp and Telegram are fantastic for friends already online, FaceTime works beautifully for iPhone users, and Viber offers a decent mix of free and paid options. When you’re looking for one app that lets you connect with anyone, anywhere, Slick really stands out as the best choice. It’s affordable, reliable, and versatile enough for almost any situation, whether you’re using it for personal stuff or work tasks. If you’re just making a quick call or managing a business across borders, Slick makes sure your voice can go anywhere without any hassle. If you’re looking to make connecting with the world a bit easier, give Slick a shot. Download the Slick app today. It’ll prove to be the best international calling app for Android and iPhone.

FAQs

It depends on what you need. If you only want free app-to-app calls, WhatsApp or Telegram works fine. But if you want to call any number worldwide, Slick is the best international calling app for affordable, high-quality calls.

To call someone who is offline or does not have the same calling app, you need an app that supports direct mobile and landline calling. Apps like WhatsApp cannot do this, but Slick can connect you to any number in 200+ countries. Just add credit or get a plan, dial the number, and you are connected instantly.

Yes, but only between users on the same app, like WhatsApp, Signal, or Viber. For true global reach, Slick offers both free app-to-app calls and low-cost plans to call mobiles and landlines anywhere.

Most “free” apps don’t support calling landlines. Slick stands out because it lets you call both landlines and mobiles in 200+ countries with crystal-clear quality and secure payments.

No. WhatsApp only supports internet-based calls between WhatsApp users. To reach someone on a landline, you’ll need an app like Slick, which connects you directly without the other person needing the app.

You can use apps like FaceTime, WhatsApp, or Slick. While FaceTime only works between Apple users, Slick lets you call any mobile or landline number. This makes it ideal for truly international communication.

Android users have many options, but most limit you to app-only calls. Slick is the best all-round choice. It offers free app-to-app calling, low-cost plans, and the ability to call any landline, mobile, or even offline number in over 200 countries.