The cheapest way to ship goods is not always the cheapest way to import them. Air freight is fast and expensive per kilogram. Sea freight is slow and cheap per unit of volume. The right choice depends on the value of the goods, their size and weight, how fast you need them and how much stock you can afford to tie up. This guide compares the two with the pricing rules that decide the bill.

How air freight is priced

Airlines charge on chargeable weight, the greater of actual weight and volumetric weight. A common volumetric formula divides the volume in cubic centimetres by 6,000 to give kilograms. A light but bulky carton of 60 × 50 × 40 cm is 120,000 cm³, or 20 kg volumetric, even if it weighs 5 kg. Rates drop as the weight rises, and there are surcharges for fuel, security and handling. Air suits high-value, light, urgent goods such as electronics, medical supplies, samples and fashion.

How sea freight is priced

Sea freight is charged per container or per cubic metre:

  • FCL (full container load). You rent a 20-foot or 40-foot container. The price per unit falls as you fill it.
  • LCL (less than container load). You share a container and pay by the cubic metre (CBM) or the tonne, whichever is larger, with minimum charges and consolidation fees.

Sea shipments take several weeks from Asia to Mombasa, plus time for unloading, clearing and trucking. Sea suits heavy, bulky, lower-value goods such as furniture, building materials, machinery and bulk stock for resale.

A comparison

Factor Air Sea
Typical transit Days Several weeks
Cost per kg High Low
Best for Light, valuable, urgent Heavy, bulky, planned
Risk of damage Lower, less handling Higher, longer exposure
Capital tied up Little More, because stock arrives later and in bulk

Freight changes your landed cost

The customs value for duty includes freight and insurance to Kenya (the CIF value), so a higher freight bill raises duty and VAT as well as the freight itself. For example, if goods cost USD 5,000 and air freight adds USD 1,500, the base for duty is USD 6,500 rather than USD 5,000. See customs valuation explained and Incoterms explained for importers for who pays what at each stage. Then add duty, IDF, RDL and VAT. The landed cost calculator and the import duty and landed cost workbook compare scenarios side by side.

Which is cheaper in practice?

Work out the landed cost per unit for each mode:

  1. Product cost per unit
  2. Freight per unit (total freight ÷ units)
  3. Insurance
  4. Duty, IDF, RDL and VAT on the customs value
  5. Port, clearing, trucking and storage

If air freight adds KES 400 per unit and the item sells for KES 6,000, air may be worth it to catch a season. If it adds KES 400 to an item selling for KES 900, sea is the only option. Include the cost of capital and the risk of running out of stock. Use the pricing and markup calculator to set the final price.

Other costs at the destination

Mombasa and Nairobi charges include terminal handling, container freight station fees, KRA scanning and verification, agency fees and transport. Delays cause demurrage (container use after the free days) and storage. A clearing agent will quote these costs: clearing agent or clear it yourself. Plan documents in advance using the import documents checklist.

Reducing the freight bill

  • Consolidate orders to fill containers
  • Pack tightly, because volume drives cost
  • Compare at least three forwarders with the same specification
  • Ship non-urgent stock by sea and urgent lines by air
  • Choose the right Incoterm so you control freight rather than paying hidden margins
  • Insure the cargo, because the premium is small next to the risk

More ideas are in how to lower your landed cost legally.

Risks

Sea shipments can be delayed by weather, port congestion or documentation problems. Air shipments can be bumped from flights. Whatever the mode, deal with reputable forwarders, confirm the documents and track the shipment. Suppliers' risks are covered in importing from China: risks and checks.

Frequently asked questions

What is a CBM? A cubic metre, calculated as length × width × height in metres. Sea LCL freight is quoted per CBM.

Is insurance compulsory? It is usually part of the customs value (CIF). Even when not required, cargo insurance protects against loss and damage.

How do I know the volumetric weight for air? Multiply length, width and height in centimetres and divide by 6,000 to get kilograms, then compare with the actual weight.

Can I mix modes? Yes. Many importers send urgent lines by air and bulk stock by sea.