In 2014 Russia took control over Crimea, and significant numbers of Ukrainian investors pursued investment claims against Russia regarding investments in Crimea made prior to the annexation.Thus, a fundamental concern is the applicability of the Ukraine-Russia BIT to such investments.The BIT empowers Ukrainian investors to initiate arbitration for compensation if Russia expropriates any Ukrainian investments on its territory. In order for the investors’ capital in Crimea to qualify as “investments” under the BIT, the tribunals had to determine whether Crimea constituted a part of the Russian “territory”. Even though Crimea was de facto controlled byRussia, de jure the Russian sovereignty over it had been questioned. As of time of the Thesis at least 10 cases were initiated and in seven of which decisions on responsibility and compensation were made. Investors are now enforcing the decisions in different jurisdictions facing jurisdictional challenges from Russia`s side. In 2019, Russia changed the strategy deciding to actively participate in the cases, which may play a decisive role on further developments of the disputes. The paper will examine whether investment tribunals in the Crimean cases have authority to hear them and the award to stand during set-aside/enforcement proceedings from the perspective of different enforcing jurisdictions, as well various litigation tactics and strategies presented by Russia.