This article provides general information, not legal, regulatory or financial advice. Requirements depend on the applicable contract, authority and jurisdiction.
The layers
Maritime law — also called admiralty law — governs ships, the people on them, the cargo they carry and the sea they operate in. It is one of the oldest bodies of commercial law and one of the few that is genuinely international in operation, because a ship is a moving object subject to several legal orders at once.
This is an orientation, not legal advice. Every real question needs a lawyer in the relevant jurisdiction.
| Layer | Source | Examples |
|---|---|---|
| Public international law | Treaties between states | UNCLOS; IMO conventions |
| Flag state law | The state of registration | Manning, certification, criminal jurisdiction on board |
| Coastal / port state law | The state whose waters the ship is in | Port State Control, pollution rules, customs |
| Private contract law | The parties' agreements | Charterparties, bills of lading, management agreements |
| Domestic admiralty procedure | National courts | Ship arrest, maritime liens, enforcement |
The key conventions
UNCLOS — the United Nations Convention on the Law of the Sea — sets the framework of maritime zones and the rights and duties of flag, coastal and port states.
IMO conventions govern safety and environment: SOLAS (safety of life at sea), MARPOL (pollution prevention), STCW (crew training and certification), COLREG (collision regulations), the ISM Code (safety management), the BWM Convention (ballast water), and the Hong Kong Convention on ship recycling, in force since 26 June 2025.
ILO contributes the Maritime Labour Convention, 2006, covering seafarer employment and welfare, amended in June 2025 with entry into force expected in late December 2027.
Cargo liability regimes — the Hague, Hague-Visby, Hamburg and Rotterdam Rules — govern carrier obligations under bills of lading, and which applies depends on the contract and jurisdiction.
Liability and compensation conventions cover oil pollution, bunker pollution, wreck removal, salvage and the limitation of liability for maritime claims.
Jurisdiction: who governs the ship
The bars represent coastal state authority; the line represents flag state authority. On the high seas the flag state governs almost exclusively. In port, the coastal state's authority is close to total. Everything in between is a negotiated balance, with the right of innocent passage through the territorial sea as one of its central features.
Concepts worth understanding
Maritime lien. A claim that attaches to the vessel itself, surviving a change of ownership in many jurisdictions. Categories vary but commonly include crew wages, salvage, and certain damage claims. It is why unpaid crew wages are a very serious matter for a vessel's marketability.
Ship arrest. A claimant may arrest a vessel in a jurisdiction to obtain security for a maritime claim. Arrest is fast, disruptive and expensive, which makes it a powerful practical remedy — and a serious operational risk for owners with unresolved disputes.
Limitation of liability. Shipowners may in many circumstances limit liability for maritime claims to an amount calculated by reference to tonnage, under applicable conventions and national law, subject to conduct-based exceptions.
General average. An ancient principle: where a sacrifice or extraordinary expenditure is made for the common safety of ship and cargo, the loss is shared proportionately between all interests. It arises after groundings, fires and salvage events, and it is administratively heavy.
Salvage. Salvors who successfully save property at sea are entitled to a reward, with special provisions where environmental damage is prevented.
Seaworthiness. A central obligation — the vessel must be fit for the intended voyage — and its breach undermines defences across cargo claims, charterparty disputes and insurance.
How disputes are actually resolved
Most shipping disputes never see a court. They are resolved by:
- Negotiation, usually informed by the strength of the documentary record
- Mediation, increasingly used for cargo and charterparty disputes
- Arbitration, the dominant forum, most commonly in London, Singapore, New York or Hong Kong depending on the contract
- Court litigation, particularly for arrest, enforcement and collision proceedings
Charterparties routinely specify arbitration and governing law. Those two clauses determine more about the outcome of a future dispute than most of the operational terms combined.
What this means operationally
- Documents win disputes. Statements of fact, letters of protest, logs, photographs and contemporaneous notes decide outcomes far more often than legal argument does.
- Time bars are absolute. Cargo claims, demurrage claims and bunker claims all run to deadlines that the merits do not override.
- Notify insurers early. Late notification prejudices cover.
- Preserve evidence immediately after any incident, including data — engine logs, alarm printouts, ECDIS records, CCTV.
- Know your governing law and forum before something happens, not after.
general information only, not legal advice. Applicable conventions and their national implementation vary by jurisdiction. Zone chart is conceptual. Reviewed by the Zeaclub Editorial Team, 24 August 2026.
Frequently asked questions
What is maritime law?
The body of law governing shipping, navigation, seafarers, cargo carriage and marine commerce, combining international conventions, flag and coastal state law, and private contract law.
What is the difference between maritime law and the law of the sea?
The law of the sea, principally UNCLOS, governs relations between states over maritime space. Maritime or admiralty law governs private commercial relationships involving ships.
Can a ship be arrested for unpaid bills?
For maritime claims, in jurisdictions permitting arrest, yes. It is a common and effective means of obtaining security.
Which law applies on board a ship?
Primarily the flag state's law, subject to coastal and port state jurisdiction when in their waters, and subject to whatever law the parties chose in the relevant contracts.