This journal was created because of the consideration of the Government of the Republic of Indonesia in determining the legal status of ships with Indonesian flag. The consideration is that the right to fly the Indonesian flag as a national flag on a ship is in force in Indonesia, because ships with Indonesian flag are part of Indonesian territory. This research was conducted with a quantitative methodology approach.The results of the study concluded that ships in Indonesia were entitled to legal protection from the Indonesian government and were required to fulfill the maritime conditions of the ship in accordance with the laws and international conventions ratified by the Indonesian government.The stages of determining the nationality of a ship determine the legal status of the ship as referred to in article 154 of Act Number 17 of 2008 concerning shipping, namely: Measurement, Registration and Determination of Ship Nationality.