In June 2017 a wide-ranging and protracted dispute between several members of the Gulf Cooperation Council (GCC) simmered over into the public sphere with the United Arab Emirates (UAE), Bahrain and Saudi Arabia all severing diplomatic ties with Qatar. This diplomatic dispute is accompanied by a number of port state and coastal state measures which includes the denial of the use of ports and the denial of innocent passage to vessels either linked to Qatar or carrying cargo linked to Qatar. This paper will use the current law of the sea framework to analyse the legality of the UAE’s, Bahrain’s and Saudi Arabia’s Qatar-related restrictions upon international shipping. This paper concludes that in both cases the three GCC states have a valid jurisdictional basis to adopt such measures, but the limitations of customary international law and the United Nations Convention on the Law of the Sea (UNCLOS) are arguably not being followed. The conclusion also touches upon whether the compulsory dispute settlement procedure found in Part XV of UNCLOS presents another avenue for flag states to challenge the restrictions on innocent passage imposed by Saudi Arabia and Bahrain as parties to UNCLOS.