Admiralty law or maritime law is a distinct body of law that governs maritime questions and offenses. It is a body of both domestic law governing maritime activities, and private international law governing the relationships between private entities that operate vessels on the oceans. It deals with matters including marine commerce, marine navigation, marine salvaging, shipping, sailors, and the transportation of passengers and goods by sea. Admiralty law also covers many commercial activities, although land based or occurring wholly on land, that are maritime in character.

Admiralty law is distinguished from the Law of the Sea, which is a body of public international law dealing with navigational rights, mineral rights, jurisdiction over coastal waters and international law governing relationships between nations.

Although each legal jurisdiction usually has its own enacted legislation governing maritime matters, admiralty law is characterized by a significant amount of international law developed in recent decades, including numerous multilateral treaties.

The key to South African Admiralty Jurisdiction and Practice is the maritime claim, whose definition will be found in the Admiralty Jurisdiction Regulation Act 1983 read with the Admiralty Court Rules of 1997. Without a maritime claim as defined by the Act, a litigant has no recourse in Admiralty in South Africa nor does the High Court in Admiralty have jurisdiction. If a Court regards a matter as essentially a common law cause, without its nature or subject matter being marine or maritime, the Court will disallow jurisdiction in Admiralty. Choosing the correct maritime claim is important when a claimant seeks to rank its claim against other claimants upon a distribution of the funds derived from the sale of a vessel in execution.

As a result of the Admiralty Jurisdiction Regulation Act, a foreign claimant is allowed access to the South African Court in Admiralty and for the first time an asset situated within the jurisdiction would be sufficient to found the jurisdiction of the Court in an action between two foreigners. Therefore an action in rem presupposes a maritime asset within the jurisdiction of any of the Provincial Courts whether coastal or inland, may be commenced in any such Court. In terms of the Act, the Court has the power to impose conditions upon any arrest or attachment such as the provision of security by Plaintiff, Defendant or any intervening party. The decision of whether to proceed by way of an arrest with an action in rem or by an attachment with an action in personam is often a difficult one. The Court also has a discretion to arrest maritime property as security for a maritime claim being brought to Court or arbitration anywhere. This is one of the most powerful measures of the Act and is one of its newest and trite and unusual consequences thereof. The purpose of a security arrest is to bring the res (item or thing), and not the person of the Defendant, before the Court.

If all the requirements of the Act have been met the Court has no discretion to refuse to grant an Order of Arrest or attachment, but however the Court has a discretion to decline to exercise what would otherwise be competent jurisdiction if it is of the opinion that another more appropriate tribunal anywhere will exercise jurisdiction. Therefore where an arrest or attachment has already taken place, the effect of the Court relying upon Section 7 of the Admiralty Jurisdiction Regulation Act and defining jurisdiction will be that the arrest or attachment falls away.

The detention of a ship by arrest or attachment is serious with the potential of causing huge losses for the ship owner as a result of interrupted operation. If a ship owner provides the opponent with adequate security, a vessel will immediately be released upon the lodging of the adequate security. South African Admiralty procedure has also adopted the caveat release, in terms of Admiralty Rule 4(4), which enables a claimant who intends to institute an action in rem against any property which has already been arrested or attached to file a caveat release with the Registrar. Any other arresting or attaching parties are required to give notice to the party who files the caveat, who is asked for its consent to the release