If you are importing goods into the US, you need a Customs Assigned Importer Number (CAIN). This is especially critical for foreign importers acting as the importer of record, as the US customs uses it to identify the importer and track shipments.

But what exactly is a CAIN, who else needs it, and how do you get it?

In this guide, Blackthorne IOR answers all your questions concerning the customs-assigned importer number.

What is a Customs Assigned Importer Number (CAIN)?

A customs-assigned importer number (CAIN) is a unique number the US Customs and Border Protection (CBP) issues to foreign importers and US residents who prefer CAIN over SSN. 

Foreign importers are individuals or entities without a US tax identification number, such as an Employer Identification Number (EIN) and Social Security Number (SSN).

To import into the US, you must have a tax ID to file customs declarations for each shipment. The ID is the number that identifies you in relation to the importer security filing (ISF), customs Bonds, and customs Entry.

Resident importers (importers residing in the US) can use their business EIN or SSNs to import. But foreign importers must obtain a customs-assigned number from CBP to import into the US.

Who Needs a CAIN?

The customs-assigned importer number is primarily for foreign importers. However, US residents can also request CAIN under certain circumstances.

Foreign importers and US citizens who need a customs-assigned importer number include:

  • Foreign companies importing via a Foreign Importer of Record (FIOR)
  • Individuals who don’t have an SSN but wish to import into the US
  • Individuals without an IRS number
  • US residents with an SSN but prefer to use CAIN for all entry documents
  • Individuals who have yet to apply for an IRS Number or SSN

Step-By-Step Guideline to Obtaining a CAIN 

So, how do you get the customs-assigned importer number?

Here is a step-by-step guide to obtaining a CAIN:

Step 1: Complete CBP Form 5106

Head to the US Customs and Border Protection official website to access the CBP Form 5106. This form establishes your importer record with CBP and requires you to provide the following information:

  • Legal business name and address
  • Contact details
  • Types of business (corporation, partnership, individual)
  • Country of registration
  • Primary business activity

With the CBP Form 5106, you can:

  • Create a new importer record (if you are a new CAIN applicant)
  • Update existing importer details (e.g., address, ownership, contact info)
  • Reactivate an inactive (void) importer number

Step 2: Provide Business Identity Proof

CBP may request additional documentation to verify your identity and business legitimacy. Documentation you may need includes:

  • Business registration/Certificate of incorporation
  • Proof of address (utility bill, lease agreement, or bank statement)
  • Government-issued identification for company officers or owners
  • Power of attorney if a customs broker or IOR is acting on your behalf

Step 3: Submit the Application

You can submit the Form 5106 electronically or manually:

Electronically

You can file Form 5106 through a licensed customs broker. The customs broker uses the Automated Broker Interface (ABI) or the ACE Secure Data Portal.

Manually

If you don’t have access to ACE or ABI systems, download Form 5106 from the CBP website, fill it out, and sign it.

If you have already been assigned to a center, scan the Form 5106 and send it to the correct Center of Excellence (as a PDF). You can find the Center’s email address for your shipment from the Centers of Excellence and Expertise Directory

The subject line of the email should include:

  • “New 5106 Add” for new importer records, or
  • “5106 Update” if updating existing records

If you have yet to be assigned to a center as an importer, you can refer to the port location contacts to submit Form 5106.

And if your importer status reads “Void”, you can send an inquiry to bondquestions@cbp.dhs.gov with Void IR# naming convention in the subject line for reactivation.

Step 4: CAIN Receipt and Management

Once approved, CBP assigns your customs-assigned importer number. You can use the number for import filings, customs entries, and compliance documentation.

If your company name, address, or ownership changes, you must update Form 5106 within 30 days of the change.

Customs Assigned Importer Number Look-up

What if you are unable to find your customs-assigned importer number?

Sometimes, you or your representative may want to look up an existing CAIN, especially when:

  • You previously filed entries, but don’t have your CAIN record
  • A new customs broker or importer of record (IOR) service is taking over account management
  • You need to confirm whether your IOR is still active or deactivated.

In such circumstances, only authorised parties can request a CAIN look-up from CBP. These parties include licensed customs brokers and employees of the importer of record or consignee.

How to Request a CAIN Lookup

Licensed customs brokers and IOR or consignee employees can look up a CAIN in this quick guide:

  1. Licensed Customs Brokers

Follow the following steps to find a CAIN on behalf of your client:

  • Email the request to the assigned Center of Excellence and Expertise (Center)
  • Attach an active, signed Power of Attorney (POA) that lists the client’s name and address
  • The Center will verify the POA and provide the importer’s CBP-assigned number
  1. Importer of Record (IOR) or Consignee Employees

If you are a senior manager, such as a CEO, CFO, President, or Vice President:

  • Email the assigned Center from your official company email address
  • Request the CBP-assigned number for your company and include your title when signing the request.

For non-managerial employees:

  • You must include a signed letter from one of your company’s senior managers, authorising you to obtain the CAIN.
  • The letter must specify your employment name, position, and the purpose of the lookup
  • Attach the signed letter when emailing the assigned Center for the CAIN.

FAQs

1. How long does it take to get a CAIN?

It takes CBP 2 business days to create and activate a new importer number if you have correctly submitted Form 5106.

2. Does a CAIN expire?

No. A CAIN doesn’t expire. However, you must update your information with CBP within 30 business days if you change your business details, such as your name, address, or ownership.

3. Is there a fee to obtain a CAIN?

CBP doesn’t charge a fee for issuing an importer number. However, customs brokers and IOR service providers may charge an administrative fee for preparing and submitting the application.

4. Can a company have multiple importer numbers?

Yes. Your company may have multiple importer numbers if you operate under varied trade names, divisions, or legal entities. You must register each number separately with CBP.

5. What happens if an importer doesn’t have a CAIN or EIN?

CBP cannot process import entries without an importer number. As such, your shipment may be delayed or held at customs until you register your import record and have a valid importer number.

Challenges Associated with Obtaining a CAIN

Obtaining a customs-assigned importer number is straightforward. However, as an importer, you may face various challenges, including:

Filling Out Form 5106 is Time-Consuming

The form requires detailed identity information, which can be difficult to locate if you are a new business. Also, even as an existing importer, you may need to fill a separate form for every high-value shipment, accurately and consistently.

It’s Challenging to Choose Between Electronic and Manual Submission

CBP processes electronic submissions faster and highly recommends it. However, you have limited access to ACE and ABI systems, especially if you are a foreign importer. 

And if you are inexperienced in manual registration, it’s even more challenging to identify the correct email or port of entry to which you can send the form.

Determining the Appropriate Center of Excellence is Complex

Your shipment determines which Center of Excellence is appropriate. But identifying the accurate customs classification code or product category can be challenging. And sending the form to multiple locations is discouraged because it slows CAIN processing.

Limited Visibility into Application Status for Manual Requests

Manual CAIN requests don’t support real-time tracking. As the importer, you must follow up with CBP to confirm receipt of the form and the status of your request.

Overcome the CAIN Acquisition Complexities with an Importer of Record (IOR)

You probably don’t want to experience the hassle of requesting a Customs-Assigned Importer Number (CAIN), let alone fulfilling all the requirements of importing into the US. And that’s understandable. The good news is, you don’t have to!

Because you can opt for an importer of record (IOR) shipment.

With an experienced importer of record such as Blackthorne, you can import into the US compliantly with minimal involvement. The IOR fulfills all global supply chain requirements, from preparing documentation to customs clearance.

And if Blackthorne imports on your behalf, you have a one-stop shop that caters to all your importation needs, including:

  • 360-degree compliance: We ensure your shipment complies with all US import rules and standards, is safely transported, and is delivered within the agreed timeframe.
  • Import/export licensing fulfillment: We identify all applicable licensing requirements and obtain the necessary permits and approvals before initiating shipping.
  • Importer registration and customs clearance: Blackthorne handles the importer registration process and clears the goods through customs on your behalf.
  • Door-to-door equipment transportation: You don’t have to worry about the safety of your equipment or when your shipment arrives. You can track it from dispatch through transit to the last-mile delivery.
  • Equipment, installation, maintenance, and support: Technical products can be challenging to install. And some product licences need renewal. Plus, your equipment must remain compliant even when regulatory requirements change.

We ensure safe installation, quality maintenance, and offer ongoing virtual and physical support so you don’t worry about post-delivery compliance and equipment failure.

Hence, if requesting a CAIN already feels overwhelming, Blackthorne is taking care of it.

You can email us at sales@blackthorneit.com or hit this call button so we can start shipping your products to the US.