Deviation - FAQs Deviation is a topic that often comes up with our Members. Deviation is important as it can have significant implications under a contract of carriage as well as for Members’ Club cover. These FAQs address the key basics of deviation. Articles Sophie Davis Published: April 07, 2026 Contact author Download article pdf What is Deviation? What is the reason for it?  Deviation at its simplest is an unjustified departure from the prescribed route but also includes unreasonable delay in performing the contractual voyage. In the absence of a term in the contract that stipulates the prescribed route, the contractual route is presumed to be the direct geographical route between the port of loading and the port of discharge. However, evidence is also permitted to show what the usual or customary shipping route is (where this differs from the direct geographical route).  In a contract of carriage such as a bill of lading, the Carrier must usually call at the ports stated by the usual or customary route and with due or reasonable despatch. Whilst a voyage charterparty will often contain a term that the vessel must undergo the contractual voyage by the route stipulated and without delay (the duty of utmost despatch). If the vessel deviates in the absence of a suitable liberty clause or for any other justified reason, then it could represent a breach of contract.  The Club previously published an article on deviation in 2012 (see here ) and this provides a general overview of deviation and fundamental breach up to 2012.  When is Deviation justified?  It is important to highlight that not every deviation will be unlawful. It will always depend on the relevant contractual terms and liberties granted therein, as well as the facts.  Article IV, rule 4 of the Hague-Visby Rules (such as may govern a contract of carriage) sets out limited circumstances in which a deviation may be permitted and would not constitute a breach of the Convention