Shipping Container Classifications and Certification: What You Need to Know
If you’ve ever searched online to buy a shipping container, you’ve probably seen terms like WWT, CW, AS IS, IICL, ISO, or CSC and wondered what they actually mean. These classifications describe a container’s condition, certification, and intended use, and understanding them is essential before you buy.
Whether you need a shipping container for storage, international shipping, or a conversion project like a tiny home or office, knowing how containers are graded will help you choose the right option and avoid costly mistakes.
Shipping Container Condition Classifications
Shipping containers are typically classified based on condition and certification status. Since most containers spend years in active service, wear and tear is normal. While there is no universal grading system, the following classifications are the most commonly used across the industry.
New (One-Trip) Shipping Containers
Best for: Long-term storage, modifications, resale value, and aesthetics
New (one-trip) shipping containers are manufactured overseas—usually in China—and loaded with cargo for a single international trip. After that first delivery, they are sold as “new.”
Key benefits:
Like-new condition with minimal dents or scratches
No rust
Clean marine-grade plywood floors
Easy-to-open doors
No shipping line logos
Often still ISO-compliant with a valid CSC plate
Because they’ve only made one trip, these containers offer maximum lifespan and are ideal for container homes, offices, or premium storage needs.
What is a One-Trip Container? | USA Containers
IICL Containers
Best for: Leasing companies and customers needing top-tier condition
IICL stands for Institute of International Container Lessors, one of the strictest grading standards in the container industry. These containers are newer, extremely well maintained, and meet precise technical requirements.
They are typically:
Structurally excellent
Minimal cosmetic wear
Higher in price than most used containers
IICL containers are most often used in commercial leasing and international logistics.
WWT (Wind and Watertight) Containers
Best for: Storage, building projects, workshops, and conversions
A Wind and Watertight (WWT) shipping container is guaranteed to keep out wind and water. That means:
No holes in the walls or roof
Functional doors and seals
Structurally sound for non-shipping use
WWT containers are one of the most popular options because they balance affordability and reliability. While they are not automatically certified for international shipping, many can be inspected and upgraded if needed.
CW (Cargo Worthy) Containers
Best for: International shipping and intermodal transport
A Cargo Worthy (CW) container has passed a professional inspection confirming it meets the structural requirements for overseas transport.
Important distinction:
Every Cargo Worthy container is Wind and Watertight — but not every WWT container is Cargo Worthy.
Cargo Worthy certification verifies:
Structural integrity
Corner castings and frame strength
Door operation
Floor condition
CW containers can legally travel by ship, rail, and truck once paired with a valid CSC plate.
AS IS Shipping Containers
Best for: Very low-budget, non-critical use only
AS IS containers are sold in their current condition without inspection or warranty.
Common characteristics:
Visible rust
Possible holes or floor damage
Doors may be difficult to open
Not suitable for shipping or secure storage
These containers are only recommended if budget is the primary concern and the container will not be used for weather-sensitive storage or transport.
WWT vs. Cargo Worthy: What’s the Difference?
The key difference between WWT and CW containers is certification, not necessarily condition.
A WWT container may physically meet shipping standards but has not been inspected or certified.
A Cargo Worthy container has been officially inspected and approved for international transport.
Both typically include:
Working doors
Surface rust (normal for used containers)
Lifetime wind and watertight warranty
10-year structural warranty (from reputable suppliers)
What Is a CSC Plate and Why Does It Matter?
To ship a container internationally, it must have a valid CSC plate (Convention for Safe Containers), regulated by the International Maritime Organization (IMO).
The CSC plate confirms the container meets global safety standards and includes:
Container serial number
Maximum gross and stacking weight
Manufacturer details
Inspection and recertification dates
Without a valid CSC plate, most shipping lines will not accept the container.
Choosing the Right Shipping Container for Your Needs
The best shipping container depends on how you plan to use it:
Best overall quality: New (one-trip) container
Affordable, reliable storage: WWT container
International shipping: Cargo Worthy or certifiable WWT container
Modifications or builds: WWT or one-trip containers
Lowest upfront cost: AS IS container (with limitations)
Understanding these classifications helps you buy with confidence, avoid surprises, and select a container that fits both your budget and purpose.
