Cargo Insight
Maritime & Sea Cargo
Customs and Sea Freight: What Importers and Exporters Need to Know
A practical guide to customs procedures, documentation, cargo classification, duties, inspections and clearance when goods move across international borders by sea.
Why does customs matter in sea freight?
When cargo crosses an international border, it becomes subject to the customs requirements of the countries involved. Customs authorities use information about the shipment to determine how goods should be processed.
This can involve the description and classification of goods, their declared value, country of origin, importer and exporter information, and supporting documentation.
Customs is therefore an important part of the wider sea cargo journey, alongside ports, vessels, containers and inland transportation.
Requirements differ between countries and can also vary according to the type of goods being shipped.
What happens when international cargo crosses a border?
Customs processing generally involves several stages, although the exact procedure depends on the country, cargo and applicable regulations.
Shipment Information
Customs receives information identifying the goods, parties, origin, destination and transportation details.
Declaration
Relevant import or export declarations are submitted according to applicable requirements.
Classification
Goods are classified using the applicable tariff and customs classification system.
Assessment
Customs may assess duties, taxes, restrictions or other requirements associated with the shipment.
Inspection
Cargo may be selected for documentary review, physical inspection or other regulatory checks.
Clearance
Once applicable requirements are satisfied, the cargo can proceed through the import or export process.
What is the difference between importing and exporting?
Exporting refers to goods leaving one country for another destination. Importing refers to goods entering a country from an overseas origin.
Both processes involve customs requirements, but the responsibilities, declarations and regulatory procedures can differ.
Exporters generally need to consider
- Accurate cargo descriptions
- Export declarations where required
- Commercial documentation
- Country of destination
- Applicable export controls
- Carrier and shipping information
Importers generally need to consider
- Import declarations
- Customs classification
- Declared customs value
- Duties and taxes
- Import restrictions
- Required permits or certificates
“The ocean carries the cargo, but customs determines how it enters the market.”
International freight does not end when a vessel reaches port. Customs processing is part of the transition between international transportation and the domestic supply chain.
Documents that can support customs clearance.
Customs authorities rely on accurate information to assess and process international shipments.
Commercial Invoice
Provides information about the transaction, seller, buyer, goods, quantities and declared value.
Packing List
Provides information about packages, quantities, dimensions and weights within the shipment.
What information can customs authorities look at?
Accurate shipment information is fundamental to customs processing and helps authorities determine how cargo should be treated.
Goods Description
The description should clearly identify what is actually being imported or exported.
HS Classification
Goods are classified under the applicable Harmonized System or national tariff classification.
Customs Value
The declared value can be relevant when determining applicable duties and taxes.
Country of Origin
Origin information can affect customs treatment, trade agreements and import requirements.
Importer Information
Customs documentation identifies the relevant importer or consignee and other parties.
Supporting Documents
Permits, certificates and other documents may be required depending on the goods.
What is an HS code?
The Harmonized System, commonly known as the HS, is an internationally used system for classifying traded goods.
Customs authorities use tariff classifications to identify products and apply the relevant customs treatment.
Different products can have different classifications, making accurate product identification important when preparing an international shipment.
Why classification matters
The applicable classification can influence customs duties, taxes, statistical reporting, import controls and other regulatory requirements.
How does customs value relate to sea freight?
Customs authorities may need to determine the value of imported goods for the purpose of assessing duties and taxes.
The rules for determining customs value vary between jurisdictions and can depend on the transaction and circumstances of the import.
Information that can be relevant
- Commercial invoice value
- Currency of the transaction
- Quantity of goods
- Country of origin
- Freight-related costs
- Insurance where applicable
- Other relevant adjustments
Customs and sea freight in Australia.
Australia has established customs and border processes for goods entering and leaving the country by sea.
Australian Imports
Imported goods entering Australia can be subject to customs processing, duties, taxes, biosecurity controls and other requirements.
Australian Exports
Exporters may need to meet declaration and regulatory requirements before goods leave an Australian port.
Customs and sea freight in Papua New Guinea.
Imported cargo arriving in Papua New Guinea is subject to applicable customs and border requirements before it can enter the domestic market.
Port Moresby
Port Moresby is an important maritime gateway for international cargo serving the National Capital District and surrounding areas.
Lae
Lae is an important commercial and industrial centre and a major gateway for cargo entering Morobe Province and other parts of Papua New Guinea.
Why might customs inspect cargo?
Customs and border authorities may inspect shipments as part of routine controls, risk assessment or regulatory enforcement.
Document Verification
Authorities may compare declarations with supporting documentation.
Cargo Identification
Physical examination may help verify what has actually been declared.
Biosecurity Controls
Certain goods may require inspection because of agricultural or biosecurity risks.
Restricted Goods
Controlled or regulated products may require additional checks or permits.
Risk Assessment
Customs authorities use risk-based processes to identify shipments requiring further attention.
Regulatory Compliance
Inspections can help confirm compliance with applicable border and import regulations.
“A shipment can be commercially simple but still require careful border preparation.”
Food, plant material, animal products, timber and other biological materials can be subject to additional biosecurity requirements depending on the destination.
What are customs duties and import taxes?
Customs duties and import taxes are charges that may apply when goods enter a country. The amount and applicable charges depend on the destination country's laws and the characteristics of the shipment.
Not every shipment is treated in the same way. Tariff classification, customs value, origin and applicable trade arrangements can all influence the treatment of goods.
Factors that can influence customs charges
- Product classification
- Declared customs value
- Country of origin
- Type of goods
- Applicable tariff rates
- Trade agreements
- Import exemptions or concessions
A practical customs checklist for importers and exporters.
Preparing customs information before the shipment reaches the port can help identify potential documentation issues.
Identify the Goods
Know exactly what is being shipped and how it is packaged.
Check Classification
Determine the appropriate customs classification for the goods.
Confirm Value
Ensure commercial and customs value information is accurate.
Check Origin
Confirm the relevant country-of-origin information.
Review Restrictions
Determine whether the goods require permits, licences or special approvals.
Prepare Documents
Make sure the relevant customs and shipping documents are complete and consistent.
Issues that can delay or complicate cargo clearance.
Customs processing can become more complicated when shipment information is incomplete, inaccurate or inconsistent.
Common problems include
- Incorrect cargo description
- Incorrect HS classification
- Missing documentation
- Inconsistent invoice information
- Incorrect declared value
- Missing permits
- Undeclared restricted goods
- Incomplete consignee information
Who can help with customs and international freight?
Importers and exporters may work with freight forwarders, customs brokers or other logistics professionals when arranging international shipments.
Their role can include coordinating documentation, transportation and customs-related processes.
Their involvement can include
- Preparing shipment documentation
- Coordinating with carriers
- Submitting customs information
- Arranging cargo clearance
- Coordinating port procedures
- Arranging inland transportation
Customs considerations for Australia–PNG sea freight.
Cargo moving between Australia and Papua New Guinea crosses an international border and therefore requires attention to the rules of both countries.
Before Departure from Australia
Exporters should confirm applicable Australian export requirements and ensure shipment information is prepared correctly before cargo enters the international shipping network.
On Arrival in Papua New Guinea
Import cargo must satisfy applicable Papua New Guinea customs, border, biosecurity and regulatory requirements before entering the domestic market.
“Good customs preparation begins before the vessel sails.”
Customs should be considered during the planning stage, rather than treated as something that happens only after the cargo reaches its destination port.
Understanding customs as part of the sea freight journey.
Customs is an essential part of international sea freight. Importers and exporters need to understand the documentation, classification, valuation and regulatory requirements that apply to their cargo.
Accurate information can make the customs process easier to understand and helps ensure that the shipment is prepared for the relevant border requirements.
Requirements differ between countries and cargo types, so current official requirements should always be checked before an international shipment is arranged.
Customs is only one component of the wider maritime network. Ports, vessels, containers, shipping routes and inland logistics all connect to the same journey.
Continue exploring the subject through the main Sea Cargo guide .
Callum Whitmore
Callum Whitmore writes about sea cargo, maritime transportation, shipping routes and ports, with a particular focus on Australia, Papua New Guinea and the wider Pacific.