A covenant is an act by which one or more people commit themselves to one or more other people. Agreement is the most important source that gives birth to an engagement. This article discusses the Strength Study between Law Number 17 Year 2008 concerning Ports by looking at the Cooperation Agreement entered into by PT. Pelabuhan Indonesia III (Persero) with PT. Gresik Jasatama in accordance with the Civil Law is as regulated in Article 1338 paragraph (1) of the Civil Code which takes longer than Act No .: 17 of 2008 concerning Sailing, this is in accordance with the Lex Posterior Derogat Priori principle. The Ministry of Transportation has the authority and authority at the port as stated in Law No .: 17 of 2008 concerning Shipping and Government Regulation Number 61 concerning Ports so that there is no misunderstanding free from the influence of conflicting interests.