Do International Letters Need Custom Form?

Yes, all mails originating outside of the custom territories of the United States of America, which excludes the District of Columbia and Puerto Rico as mails sent to both the states are subject to customs examination.

Here are some exceptions which are not subject to customs examination,

  • Mails sent to ambassadors, also known as chiefs of diplomatic missions and ministers of the foreign countries, don’t go through customs.
  • All mails consisting of official documents addressed to diplomatic officials of the U.S government exempt custom forms.  
International mail

By now, you must be clear that you need to submit a customs declaration form if your letter is not for diplomatic missions.

How to complete the procedure is striking your mind? Yes, we have got you covered in this article. So, I will discuss customs declaration forms, and what do’s and don’ts you must follow while filling one. 

Do International Letters Need Custom Form?

Custom declaration form CN 23

A customs declaration is a form that is mandatory to fill when transporting goods like musical instruments, alcohol, animal meat, technological goods, seeds, plant material, and other food products from one country to another. One has also to fill up the customs declaration form when mailing an international letter.

The customs declaration form helps the customs have full control over the goods for economic and security purposes. Some countries also charge custom duty for goods and mail. 

Irrespective of whether you are traveling on board or mailing the goods, you have to declare all the goods in the customs declaration form and pay duty for the goods. Some countries have partial custom duty where they charge on some goods exempt from duties.

Different Types of Custom Declaration Forms

When an individual travels along with the goods, the customs declaration form is called a customs arrival card or landing card. The traveler has to submit the form to the customs department of the country before entering. 

On the other hand, when an individual ships goods from their country, they will have to sign a custom declaration form along with a commercial or proforma invoice. At the same time, the importer has to also sign an ATA carnet or import declaration form during the time of arrival of the goods. During shipments, one has also to prove the HSC or Harmonized System Code used to define different types of goods. 

The importer has to submit all the necessary documents like certificate of origin, information about goods to the customs, and any errors that might delay or confiscate the goods. Due to these reasons, importers offer custom brokerage to officers to release the goods. 

Moreover, custom duties are not limited to goods as one has also to fill up a custom declaration form for every person crossing the border. Some countries demand one form per family, while others demand a custom declaration form for every individual. 

Where can I get a Customs Declaration form?

Are you ready with your mail, and do you want to send off the mail across the borders quickly?

Head straight to your post office to get the custom declaration form. You can also fill up custom forms online, but we would like to recommend offline options because it’s your first time, and you need guidance from your experts.

Moreover, if you are using a private mail service, they can guide you through filling the custom declaration form. 

How do I fill out a customs form for international shipping?

When filling custom forms, you must provide correct information to ensure that your international shipment experience smooth custom formalities. You can add all the information and necessary documents to the invoice or dedicated custom documents. The details also vary from one courier service to the other. Hence you must finalize the details with your male partner. However, you also have to understand that different countries have different international shipping procedures; therefore, prepare wisely. 

To ensure that you can fill the customs form correctly, you have to double-check the information mentioned below,
➤ Name and address of both the sending party and the receiving party.
➤ Detailed information of all the items inside the package. 
➤ Quantity.
➤ Pricing.
➤ Weight.
➤ Dimensions.
➤ Invoice details and
➤ Detailed information about terms of payment.

Moreover, you will also have to check for special requirements. For example in the United States of America, Canada, the Philippines, and Mexico required AMS or Automated Manifest System for sending parties. 

What is an AMS or Automated Manifest System?

The automated manifest system is an initiative of the U.S. Customs and border protection force adopted since 2004. AMS is an electronic information transmission system which is for safety-related operations. So, if you are shipping to the US or Canada, you will have to fill the AMS form 24 hours before the departure. 

Can You Fill the Customs Form Online?

Yes, you can fill customs forms online at the official website of USPS. You can also find out various details on the official websites. The official website of USPS also describes that you don’t need to fill up a custom’s form if you are sending first-class international mail consisting of non-negotiable documents, and it must weigh under 16 Oz approx. 

Do I need a Custom form to Mail to Canada?

As mentioned above, if your shipment weighs under 16 oz approx, you don’t have to fill up the customs form. At the same time, if your documents weigh more than 16 oz, you will have to fill up the customs form on the official website of USPS or visit your nearest post office. First-class international mail is also the most affordable option for sending letters to your loved ones. One of the best advantages of using their service is they are available in 190 countries.  


No more trips to the post office as you can fill up your custom form online, but you will have to be careful as any error can land the receiving party in trouble. For instance, you have to ensure that you don’t enter the wrong classification of products, incorrect product description, and incorrectly reveal the bar code. Filling up a custom form is easy if you are not dealing with illegal activities. 

Avatar for Jaren Helms

Jaren worked for over a decade in the industry as a Package Handler. He started his career with FedEx but he later also worked with companies like USPS and Deutsche Post.

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