International Dialing Codes

Living in the network era, we communicate a lot through phone calls. Compared to the local or national calls, calling abroad can get a bit more complicated. So, to be able to keep in touch at a global level, international dialing codes are very important. 

This is a complete guide on country codes, national direct dialing, IDD prefixes and everything connected to international dial codes. Whether you want to call a friend in another part of the world or want to call your customers in different countries, it’s all here!

Part 1: What Are Country Codes?

The country code is the prefix you need to dial if you need to call someone in that particular country from abroad. All countries’ dialing codes have similar formats, most of them having 2 or 3 digits. There are also a few exceptions that have a single-digit code, like the USA. 

Let’s take an example to make things more clear. The country code for the UK is 44. You need to know that code when you are in another country and need to call someone back home. 

But you will also need to use the international access code and the area code for the city you are calling. A quick online search will get you the international dialing codes list to help you place your call. 

Country codes are also useful when you get international calls from numbers you don’t know. You can at least identify the country the call comes from. If you don’t know anyone there, chances are you are the target of a scam call. 

Part 2: What Is the IDD Prefix?

International telephone dialing codes are also important when you need to call from your country to a number abroad.

It’s called International Direct Dialing, and the code you need to use to place that call is the IDD Prefix. Once you have dialed it, you need to also enter the country code for the area you are calling. 

Most countries have 00 as the IDD prefix, but you need to check the list to be sure because there are quite a few exceptions. The UK has the IDD prefix 00, including ADSL and ISDN. Here are a few other examples: the USA has 011, Cuba has 110, Kenya has 000. 

That means that two calls to the UK, for instance, made from two different countries, may have to use two different IDD codes.

Part 3: What Is the NDD Prefix?

NDD stands for National Direct Dialing. It’s not all about overseas telephone codes, local calls are also important. The NDD prefix is the code you need to dial if you want to call a number in another city of the same country. 

The NDD prefix is the trunk code that every nationally dialed number begins with. After this prefix, you also need to dial the area code for the region you are calling. 

Most countries, including the UK, have 0 as the NDD prefix. But there are also exceptions, so check the list before calling. In fact, there are some countries that don’t use an NDD prefix at all.

Part 4: Case Study on International Dialing Codes

The easiest way to understand a matter as tricky as international dial codes is to take a practical example. So, let’s look at the UK. 

Let’s say you want to call someone in Bradford. If you are in London, you need to use the area code 01274 before the local number. But in fact, you have used the trunk code, or NDD prefix 0 before the actual area code. The format you use is 01274 XXX XXX.

Now imagine you want to call that Bradford number from abroad. You won’t have to use the NDD prefix anymore. Instead of 0, you will dial the country code in front of the area code. The country code for the UK is 44, so the format will be 44 1274 XXX XXX.

But you must also keep in mind what country you are in when you call Bradford from abroad. Let’s say you’re in France. You will have to dial the IDD prefix first. That’s 00 for France, so the final format for the number you need to dial becomes 00 44 1274 XXX XXX.


When it comes to calls between different countries, there are a few important aspects to remember, concerning international dialing codes. 

There are three types of codes involved, depending on the type of call you need: country codes, the IDD prefix for International Direct Dialing and the NDD prefix for National Direct Dialing. 

Here are the national and international dialing codes UK: the country code 44, IDD prefix 00 and NDD prefix 0. 

It’s extremely important to keep communicating at a global level. And even when it comes to national calls, things can be more global than you think. If you use a virtual phone, you can have any area code you need without being physically linked to that region. 

WeNumber offers such virtual lines for developing businesses, and the prices are lower than you may expect.