Cost comparison
Sea freight rates are quoted per container (FCL) or per CBM (LCL). A standard 20ft FCL from Shanghai to Rotterdam typically costs $1,200–$2,500 all-in, carrying up to 25,000 kg.
Air freight is quoted per chargeable kilogram (whichever is greater: actual weight or volumetric weight). Shanghai to London runs around $3.50–$6.00/kg all-in.
Quick maths: 1,000 kg of goods — sea might cost $400–$600 all-in (LCL); air costs $3,500–$6,000. That's a 6–10× difference.
However, for very high-value goods, the difference in financing cost (30+ days of capital tied up during sea transit vs 5 days for air) can partially offset the freight cost gap.
Transit time comparison
Sea freight transit times (port-to-port): — Shanghai → Rotterdam: 28–35 days — Shanghai → Los Angeles: 14–18 days — Hong Kong → New York: 25–30 days — Singapore → Felixstowe: 22–28 days
Add 3–7 days for origin/destination trucking, customs clearance, and port processing. Total door-to-door is often 35–45 days for Asia-to-Europe.
Air freight door-to-door: — Asia → Europe: 5–8 days — Asia → USA: 4–7 days — Asia → Middle East: 3–5 days
Air is dramatically faster — but at a significant cost premium.
When to choose sea freight
Sea freight is the right choice when:
✓ Cargo is heavy or bulky (furniture, machinery, raw materials, textiles) ✓ Goods are not time-sensitive (replenishment stock with lead time > 6 weeks) ✓ Cargo value is low relative to weight (cost of air would exceed cargo value) ✓ You ship regularly and can plan ahead ✓ Temperature-sensitive goods using reefer containers ✓ Hazardous materials (more sea options than air for DG cargo)
Sea is the backbone of global trade — over 80% of all cargo by volume moves by sea.
When to choose air freight
Air freight wins when:
✓ Cargo is high-value and lightweight (electronics, pharmaceuticals, jewellery) ✓ Deadline is tight — replenishing stock-outs, seasonal launches, urgent parts ✓ Perishables with short shelf life (fresh produce, cut flowers, live seafood) ✓ First shipment or sample orders (test the market before committing to sea) ✓ Small quantities where sea consolidation overhead isn't worth it ✓ Unpredictable demand spikes that can't be planned 6 weeks ahead
The rule of thumb: if your cargo is worth more than $15/kg and weighs under 500 kg, run the numbers on air — it's often competitive once you factor in inventory carrying costs.
Hidden cost factors
Beyond the headline freight rate, factor in:
Inventory financing: Capital tied up during 35-day sea transit vs 5-day air transit. For $100,000 of goods at 8% annual financing cost: sea costs ~$770 in interest, air costs ~$110.
Stock-out risk: Running out of stock during the 6-week sea window can cost far more in lost sales than the air freight premium.
Insurance: Air freight insurance premiums are typically slightly lower than sea (less handling, shorter transit). Both are usually 0.3%–1.0% of cargo value.
Customs: Same process and cost regardless of mode.
Fuel surcharges: Both modes have variable fuel surcharges. Air (BAF/FSC) tends to fluctuate more than sea.
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