The determination of whether to release a detained foreign warship and its crew is a crucial issue in law and in practice. This article examines the issue of the release of a detained foreign warship and its crewmembers through provisional measures by analyzing the ARA Libertad and Ukraine v. Russia cases. Specifically three issues must be examined. The first issue concerns the interpretation of military activities under Article 298(1)(b) of the U.N. Convention on the Law of the Sea (UNCLOS). On this issue, this article highlights that a threshold for deciding the preponderance of military or law enforcement elements is of critical importance when there are mixed military and law enforcement activities. The second issue concerns the immunity of a detained ship under UNCLOS Articles 29, 32, 95, and 96. In this regard, this article argues that UNCLOS Article 32 may apply to internal waters, even though opinions of the members of ITLOS were divided on this matter. The third issue relates to the question of urgency in ordering provisional measures concerning the release of a detained ship and its crew. Here, this article argues that when identifying the existence of a real and imminent risk, there is a need to consider three temporal elements: the alleged breach of the rights of the applicant State (the past), the existence of ongoing risk (the present), and the possibility of repetition or continuity of the risk (the future).