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Understand the Process of Sea Cargo and How It Works

Updated: 3 hours ago

Unloading at sea cargo

drayage and logistics solutions provider






March 3rd, 2026







We all know the role of sea cargo in global trade and how crucial it is. All the different kinds of goods– like electronics, grains, oil, and manufactured goods are transported through sea cargo. Around 90% or more of international trade is done through sea cargo. But how does sea cargo work? This is the question many people ask, especially those in the logistics industry, and to answer that question, we’ve come up with our latest blog. Here, we’ve discussed the sea freight process with some real-world stats that prove the massive scale of sea cargo. So, let’s not wait any longer and understand this in detail. 



What is Sea Cargo and Why is it Important? 

Sea cargo is basically ocean freight, where goods are transported from one continent to another through large containers and ships. Sea cargo is perfect for high-volume and is comparatively cheaper than road and air transport. 

A single container ship can carry more than 20,000 20-foot containers at once, which is the equivalent space of hundreds of thousands of cars. 

According to the US Bureau of Transportation Statistics, in 2024, America handled more than 1.6 billion metric tons of cargo at its ports, of which 40% was international sea trade.   

Every year,  major ports like Long Beach and New York move around goods worth over $300 billion. This shows the importance of sea cargo for America, and it would be wrong to say that it is not the backbone of America's economy. 

According to UNCTAD in 2024, the world sea trade was around 11 billion tons, which grew 3% after the pre-COVID period. 


sea cargo with key steps
Understand how sea cargo works

Step-by-Step Guide on How Sea Cargo Works:



Step 1: Start with Booking and Documentation: 

Sea cargo starts with booking. Here, you have to contact your freight forwarder or shipping line and get the quote through online portals or agents. Also, tell them the factors like the size of the container (20ft/40ft), route (FCL or LCL), and destination.  

Key documents required: 

  • Bill of Lading (B/L): This is like the birth certificate of a cargo.  

  • Packing List and Commercial Invoice. 

  • Certificate of Origin

Digitalization has completely taken over the USA. Customs and Border Protection (CBP) and US Customs have converted 95% of the manifests to electronic form, which has reduced the clearance time by 50%.    

Note: It is advisable to check the HS codes every time, or it may lead to delays.  



Step 2: Inland Transport and Stuffing: Pack Your Goods

After booking, the goods are stuffed. Inside the FCL (Full Container Load) one full container is yours. In LCL (Less than Container Load), multiple shippers collaborate. Stuffing is done in the warehouse, like loading from cranes and forklifts. 

Then, Inland Transport: From trucks or rail to the port. 

Some stats are really shocking– According to the Association of American Railroads, in 2024, around 1.5 million intermodal containers went from rail to ports, which reduces the highway congestion by 30%. 

Note: For the safety of hazmat goods (Dangerous goods), there are special rules; follow IMDG for that. 



Step 3: Real action: Port Handling and Loading

After reaching the port, terminal operators park cargo in the yard, which is moved by straddle carriers or AGVs (Automated Guided Vehicles) and then through quay cranes it is loaded onto the ship. All of this is tracked through the Terminal Operating System (TOS).

In 2024, the world's busiest container port i.e., Port of Los Angeles, handled 9.5 million TEUs (Twenty-foot Equivalent Units). Which means, they can berth more than 100 ships a day. 

Note: Modern ships take 24 to 48 hours for loading. 



Step 4: Travel in Sea- Voyage

This is the exciting part now, where the ship sails. The average speed of the ship is 20-25 knots (37-46 km/h). On the Asia-to-US route, the voyage takes around 10 to 45 days. 

Challenges that the sea cargo face:

  • Pirates 

  • Storms/hurricanes

  • Congestion in narrow canals (2021, $10 billion/day loss because of Suez blockage) 

Note: 

  • According to NOAA in 2024, there were around 15% voyages delay due to Atlantic hurricanes. 

  • IoT and AIS (Automatic Identification System) are used for tracking, which allows tracking the location of cargo with the help of Marine Traffic apps. 

  • For fuel efficiency, LNG-powered trucks are coming. The 2024 Maersk fleet shifted to 25% green fuel. 



Step 5: Customs Clearance and Unloading at Destination Port

Upon arrival at the port, the containers are unloaded through cranes. Custom check includes: duties and inspection, followed by de-stuffing and inland delivery. Now, you must be wondering what the door-to-door total time would be. It takes around 30-45 days on the India-US route. 

In the US, 98% cargo undergoes risk-based screening with the Automated Commercial Environment (ACE) of CBP. 

Note: In 2024 (US), around 60% of the $2.5 trillion imports came from sea.  




Factors and Costs that affect Sea Freight

The rates of sea freight keep fluctuating. In 2024, SCFI (Shanghai Containerized Freight Index) for Asia to the U.S  ranged from about $2,000 to $4,000 per 40 ft container. Factors include:

  • Fuel Prices 

  • Demand Supply (Peak time: October to December)

  • Geopolitics (The rates increased up to 200% in 2025 due to Red Sea Attacks)

Note:  According to Federal Maritime Commission data, the ocean freight rates dropped by 15% post pandemic in 2024, which ultimately benefited importers.




The Future Trends of Sea Cargo

Looking at the future, the outlook for Sea Cargo looks promising, and these are the factors that will enhance its operations. 

  • Autonomous ships (like Birkeland), 

  • Blockchain for docs (TradeLens)

  • Carbon-neutral fuels.

  • The Jones Act reforms of the USA are being discussed to boost the domestic sea trade.  

According to the US International Trade Commission, sea cargo contributes around 2 to 3% directly to the GDP, which is approximately $500 billion+ annually. 


If you still have any doubts regarding sea cargo and how it works, then let us make it super simple for you. It is a well-oiled machine that operates from booking to delivery at a massive scale to handle the US's annual cargo of 1.6 billion tons. It is very crucial for logistics professionals to understand and comprehend supply chain resilience in a better way. 

If you still have any queries regarding this topic or any other logistics-related topic, please share them, and we will try to answer them. 

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