This paper examines how Argentina’s tactical successes during the Falklands war can be understood by analysing through two of the principles of war namely, concentration of forces and surprise. Previous research on the Falklands war tends to analyse the war through the entire 74-day period or through special disciplines such as history or politics. Therefore, this study was undertaken to obtain a deeper understanding on how an inferior party can achieve tactical successes even if they are defeated in the war. HMS Sheffield and Atlantic Conveyor where both struck by the Argentinian Exocet-missiles and foundered during the war. These two particular incidents are evidence of the tactical successes for Argentina during the war, even if they were defeated. These events affected and shocked the British Task Force and knowledge regarding how they achieved tactical success is important for future warfare. The principles of war are theories explained in many states’ doctrines to explain warfare and are therefore relevant to use as theoretical framework in this study. The analytical results reveal that the tactical success can be perceived as the theory of surprise, although the theory of concentration of forces can partially explain it. The result contributes to existing research by adding a deeper understanding regarding the situations and conclusions, which can be drawn and that are relevant to studies of this nature, to improve future warfare capability for an inferior party in a conflict.