What Is an Oil Tanker? Types, Sizes and How They Work

Last updated: 26 October 2026 · By Steve Joury, cargo trip advisor at CargoHolidays

An oil tanker is a ship designed to carry oil in bulk, either crude oil from oilfields or refined products like petrol, diesel and jet fuel. The largest, called VLCCs, carry around two million barrels. Here’s how tankers work and the main types.

Key facts at a glance

  • Tankers carry crude oil or refined products in many separate tanks.
  • Size classes run from Handysize to VLCC and ULCC.
  • A VLCC carries roughly 2 million barrels of oil.
  • Modern tankers have double hulls to reduce spill risk.
  • Because of the hazardous cargo, tankers rarely carry passengers.

What is an oil tanker?

What is an oil tanker? It’s a cargo ship whose hull is divided into large tanks for liquid oil, loaded and unloaded by powerful pumps through pipelines on deck. Unlike container ships, tankers have a low, flat deck covered in pipes, with the accommodation block at the stern.

What is an oil tanker – tanker ship at sea
Oil tankers carry crude oil and fuels in many separate tanks.

Tanker size classes

ClassApprox. deadweightTypical use
Handysize10,000 – 50,000 tProducts, regional trades
Panamax60,000 – 80,000 tFits the old Panama Canal locks
Aframax80,000 – 120,000 tCrude and products, medium routes
Suezmax120,000 – 200,000 tLargest able to transit the Suez Canal loaded
VLCC200,000 – 320,000 tLong-haul crude, about 2 million barrels
ULCC320,000 t +The very largest crude carriers

Crude, product and chemical tankers

  • Crude tankers carry unrefined oil from producing regions to refineries.
  • Product tankers carry refined fuels; their tanks are coated to keep cargoes clean.
  • Chemical tankers have many small tanks, often stainless steel, for different liquids.
  • Gas carriers are a separate family – see what is an LNG carrier.
What is an oil tanker infographic – tanker classes
Oil tankers at a glance.

Safety and double hulls

After major spills in the past, international rules required new oil tankers to have double hulls – an inner and outer skin with a gap between. Tankers also use inert gas to keep oxygen out of cargo tanks and reduce fire risk, and crews follow strict safety procedures in port.

Can you travel on an oil tanker?

Almost never. Because of the hazardous cargo and strict safety rules, tanker companies generally don’t carry paying passengers. Freighter travellers sail on container and ro-ro ships instead – see types of cargo ships and shipping lines that take passengers.

Tip: You can spot a tanker from a distance: low freeboard when loaded, a flat deck of pipes and a small tower near the bow for the cargo manifold crane.

Frequently asked questions

What is an oil tanker?

A ship designed to carry oil in bulk, either crude oil or refined products, in separate tanks.

How much oil does a VLCC carry?

Roughly two million barrels.

Why do tankers have double hulls?

To reduce the risk of oil spills if the outer hull is damaged.

What is the difference between crude and product tankers?

Crude tankers carry unrefined oil; product tankers carry refined fuels like diesel and jet fuel.

Can passengers travel on oil tankers?

Almost never, because of the hazardous cargo.

Travel on a cargo ship instead

Container and ro-ro ships welcome a handful of passengers. Find your voyage.

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Steve Joury

Cargo trip advisor at Cargoholidays
Passionate about slow trip travel and sea. Steve know most shipping route and procedure to discover our beautiful world from sea on a container ship. He have been at most trips from 7 days on cargo travel to 140 days on board.
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