Laws of Armed Conflict at Sea
San Remo Manual (1994)
The San Remo Manual on International Law Applicable to Armed Conflicts at Sea, adopted in June 1994 by the International Institute of Humanitarian Law, is the most comprehensive modern codification of naval warfare law. Though not a binding treaty, it reflects customary international law. It establishes that merchant vessels are presumed to be civilian objects and may not be targeted unless they qualify as military objectives under the principles derived from Additional Protocol I (1977) to the Geneva Conventions.
- Article 52 of Additional Protocol I defines a military objective as one that by nature, location, purpose, or use makes an effective contribution to military action and whose destruction offers a definite military advantage.
- Under the San Remo Manual, a naval blockade is lawful only if it is declared, notified, applied impartially, and does not cause disproportionate damage to the civilian population (paragraphs 105–108).
- Merchant ships retain their civilian status unless they actively participate in hostilities or make a direct, substantial, and effective contribution to the enemy's war effort; transporting commercial cargo generally does not meet this threshold.
- Visit and search rights (the right of belligerent warships to board and inspect neutral merchant vessels) must precede any use of force.
● Tracked since June 12, 2026 · last seen June 12, 2026 · updates as the daily brief publishes
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