Your Complete Guide to the UK Customs Declaration Service (CDS)
-
Freya Jane
- Director of Customer's Success
If your business imports or exports goods, understanding the UK Customs Declaration Service (CDS) is no longer optional. CDS is the HMRC platform through which all customs declarations must now be submitted, and getting it right means the difference between goods moving freely and costly delays at the border.
This guide covers everything you need to know: what CDS is, how it works, how to register, and how dedicated customs declaration software can help you file accurately, quickly and in full compliance with HMRC requirements.
What is the Customs Declaration Service (CDS)?
The Customs Declaration Service, known as CDS, is HMRC’s digital platform for submitting customs declarations when importing and exporting goods to and from the United Kingdom. It replaced the older CHIEF (Customs Handling of Import and Export Freight) system as the UK’s primary customs declaration system.
CDS handles all types of UK customs declarations, including:
- Import declarations for goods arriving into the UK
- Export declarations for goods leaving the UK
- Transit declarations under the New Computerised Transit System (NCTS)
- Entry in Declarant’s Records (EIDR) and simplified declarations
Every business that imports or exports goods commercially must use CDS (or appoint a customs agent who uses CDS on their behalf). Using the right customs declaration software makes this process significantly faster and less prone to error.
Visit these pages to learn more about the CDS system:
When should you do a custom declaration?
You should do a customs declaration in the following cases:
- When sending goods outside the UK from Wales, England or Scotland.
- When sending goods to any non-EU location from Northern Ireland.
- When sending goods to EU locations from Northern Ireland.
How is CDS Different From CHIEF?
CHIEF was the UK’s previous customs declaration system, operational for over 25 years. It was built before the internet era and lacked the flexibility required for modern trade flows. CDS replaced CHIEF with a fully digital, API-driven platform that offers greater data accuracy, real-time duty calculation and better integration with third-party customs declaration software.
The key differences for businesses are:
- CDS uses a data model aligned with the EU Customs Data Model, making cross-border data exchange more consistent
- CDS allows software integrations via API, meaning tools like iCustoms can connect directly to HMRC’s systems
- CDS provides access to a wider range of financial accounts, including duty deferment and customs cash accounts
- CDS supports more detailed commodity-level data, improving classification accuracy
How Do I Register for the Customs Declaration Service?
To use CDS directly, you need to complete a straightforward registration process through HMRC. Here are the steps:
- Obtain an EORI number. An Economic Operator Registration and Identification (EORI) number is required before you can use CDS. If you do not already have one, you can apply on the GOV.UK website. Most UK businesses receive their EORI within three working days.
- Log in to your Government Gateway account. Use the same credentials you use for other HMRC services.
- Subscribe to CDS. Within your Government Gateway account, navigate to ‘Get access to a tax, duty or scheme’ and select the Customs Declaration Service.
- Set up a Duty Deferment Account (if required). If you import regularly, a duty deferment account lets you defer the payment of customs duties and import VAT to a single monthly payment, which simplifies your cash flow significantly.
- Authorise your customs software. If you use iCustoms or any other customs declaration software, you will need to authorise the software to submit declarations on your behalf through the HMRC Developer Hub.
Tip: If you use iCustoms software, our team can walk you through the authorisation process in minutes. There is no need to manage HMRC technical documentation yourself. |
Want to know why you should use CDS? Read this
What is an EORI Number and Do I Need One?
An EORI (Economic Operator Registration and Identification) number is a unique identifier assigned by HMRC to businesses that trade goods internationally. It is required for all import and export declarations submitted through CDS.
If you are a VAT-registered business, your EORI number is usually your VAT registration number prefixed with ‘GB’. If you are not VAT-registered, you will need to apply for a standalone EORI. Without an EORI, your goods cannot clear UK customs.
What is a Movement Reference Number (MRN)?
A Movement Reference Number (MRN) is a unique reference code generated by CDS each time a customs declaration is submitted. It acts as the digital receipt confirming that your declaration has been lodged with HMRC. The MRN is required by carriers, port operators and border force when goods arrive at or depart from the UK.
Customs declaration software like iCustoms automatically generates and records MRNs for every submission, creating an auditable trail for compliance purposes.
What is an Entry Summary Declaration (ENS)?
An Entry Summary Declaration (ENS) is a safety and security declaration submitted before goods arrive in the UK. It is separate from the customs import declaration and is required for goods arriving by sea from non-EU countries. ENS declarations must be submitted within specific timeframes depending on the mode of transport.
iCustoms’ S&S (Safety and Security) software automates the submission of ENS declarations, tracking goods vehicle movements across borders without manual intervention.
What are HS Codes and How Do They Affect My Declarations?
An HS code (Harmonised System code), also known as a commodity code in the UK, is a numerical classification that identifies the type of goods you are importing or exporting. The UK uses a 10-digit commodity code based on the World Customs Organisation’s Harmonised System.
Choosing the wrong commodity code can result in paying the wrong amount of customs duty, delays at the border or HMRC penalties. The UK Trade Tariff, available on GOV.UK, lists every valid commodity code and the associated duty rates.
iCustoms’ iZap tool provides instant tariff and duty calculations based on the correct commodity code, helping you verify classification accuracy before submission and avoid costly errors.
How Can Customs Declaration Software Help My Business?
Completing customs declarations manually through HMRC’s portal is time-consuming, error-prone and increasingly impractical as trade volumes grow. Customs declaration software connects directly to CDS via HMRC’s API, automating data entry, classification and submission.
Here is what the right customs software does for your business:
- Reduces errors: Automated validation checks flag classification mistakes, missing data fields and formatting errors before submission
- Saves time: Declarations that take 30 to 45 minutes to complete manually can be processed in under five minutes with the right software
- Ensures compliance: Software stays updated with HMRC rule changes so your declarations always meet the latest requirements
- Provides audit trails: Every submission is logged with its MRN, date, time and operator, giving you a complete compliance record
Calculates duties accurately: Automated tariff tools eliminate the risk of under- or over-paying import duties
What is iMagic by iCustoms?
iMagic is iCustoms’ intelligent data transformation tool. It instantly converts trade data from any format spreadsheets, PDFs, EDI files or raw data exports into perfectly structured customs records ready for CDS submission. Instead of manually re-entering trade data, iMagic reads and interprets it automatically, eliminating transcription errors at source.
What is iWiz by iCustoms?
iWiz is iCustoms’ AI-powered assistant for customs regulations. It provides instant, accurate answers to complex questions about UK customs rules, commodity codes, duty rates and CDS requirements. Think of iWiz as a customs expert available around the clock whether you need to check the correct declaration type for a specific goods movement or understand the latest NCTS requirements, iWiz gives you a clear answer in seconds.
ICustoms’ innovative tool, i.e., CDS, offers automation of customs processes for customs brokers.
What is iZap by iCustoms?
iZap is iCustoms’ tariff and duty calculation tool. It performs instant tariff lookups and duty calculations based on your commodity codes and country of origin, giving you accurate import cost projections before goods even leave the supplier. iZap is designed for fast, high-accuracy trade compliance without needing to manually search the UK Trade Tariff.
What is iNCTS by iCustoms?
iNCTS is iCustoms’ transit declaration management tool, built to handle the New Computerised Transit System (NCTS). NCTS is the UK’s digital system for managing the movement of goods in transit goods that pass through the UK without being formally imported. iNCTS ensures smooth, compliant transit declarations from departure to destination, reducing the risk of delayed releases or HMRC queries at transit offices.
What is S&S by iCustoms?
S&S (Safety and Security) by iCustoms is the tool that manages goods vehicle movement tracking and Entry Summary Declarations. It ensures that safety and security declarations are submitted on time and that vehicle movements across borders are tracked accurately. For logistics companies, freight forwarders and hauliers, S&S removes the administrative burden of cross-border vehicle compliance.
What is IDP in Customs Declarations?
IDP stands for Intelligent Document Processing. In the context of customs declarations, IDP refers to the use of artificial intelligence to automatically read, interpret and extract data from trade documents including commercial invoices, packing lists, bills of lading and certificates of origin. iCustoms uses IDP technology within iMagic to transform unstructured trade data into structured, CDS-ready declaration records without manual data entry.
How Does Customs Declaration Software Ensure Data Accuracy?
Data accuracy is the most critical factor in customs compliance. A single incorrect commodity code or missing data field can trigger a customs hold, generate a penalty notice or result in the wrong amount of duty being paid. iCustoms software ensures accuracy through:
- Pre-submission validation rules that check every data field against HMRC CDS requirements
- AI-powered classification support that suggests the correct commodity code based on product descriptions
- Automated cross-referencing of trade documents to catch discrepancies between invoices, packing lists and declarations
- Real-time duty calculation to verify that duty amounts are consistent with tariff rates and declared values
- Audit logging that records who submitted what and when, enabling post-clearance review
Do I Need Customs Declaration Software or a Customs Agent?
This is one of the most common questions from UK importers and exporters. The answer depends on your trade volume, internal expertise and the complexity of your goods.
Customs declaration software is likely the right choice if you:
- Submit more than 20 declarations per month
- Have dedicated trade or logistics staff who can be trained on the system
- Import or export a consistent range of products with known commodity codes
- Want visibility and control over your declarations rather than outsourcing compliance
A customs agent may be the right choice if you:
- Occasional one-off shipments with unusual goods
- No internal resource to manage customs compliance
- Complex goods subject to special procedures such as inward processing relief
Many businesses use iCustoms software in combination with a customs agent: the agent handles complex exception cases while the software automates the routine majority of declarations.
What is the New Computerised Transit System (NCTS) Phase 5?
NCTS Phase 5 is the updated version of the UK and EU’s transit declaration system, rolled out to align the UK with international customs data standards following Brexit. NCTS governs transit movements shipments that cross one or more customs territories without being formally imported at each border.
Phase 5 introduced new data requirements, updated message formats and tighter processing timelines. iCustoms’ iNCTS tool was built to handle Phase 5 requirements natively, ensuring that UK businesses managing transit movements are not exposed to the compliance risks associated with the system update.
How Do I Get Started with iCustoms?
Getting started with iCustoms takes less than a working day. Our team will help you connect your iCustoms software to HMRC’s CDS system, configure it for your specific goods categories and trade flows, and train your team on filing their first declarations.
You do not need a technical background to use iCustoms. Our software is designed for trade and logistics professionals, not developers.
You may also like:
Ready to streamline your Customs Declaration Process?
Boost efficiency, reduce errors, and ensure accuracy with iCDS
Subscribe to our Newsletter
About iCustoms
iCustoms is an all-in-one solution helping businesses automate customs processes more efficiently. With AI-powered and machine-learning capabilities, iCustoms is designed to streamline your all customs procedures in a few minutes, cut additional costs and save time.
Ready to streamline your Customs Declaration Process?
Boost efficiency, reduce errors, and ensure accuracy with iCDS