The first defendant, while operating ships belonging to the second defendant company, found and salvaged sunken ships in the waters of Mengolsudo, Jindo, around the beginning of February 2015, and at the end of August 2015 in the Taejongdae area, Busan, and then sold the scrap metal from the sunken ships to make a profit.

The prosecutor alleged, among other things, that the first defendant used a fish finder installed on a foreign ship to find the location of a ship that sank in the waters of Mengolsu Island without permission on 29 January 2015, in violation of the Territorial Seas and Contiguous Areas Act (the Act). The second defendant company was unaware of the first defendant's actions. Both defendants were charged with the offence of violating the Shipping Act by transporting cargoes such as hulls and scrap metal twice without registering to conduct maritime cargo transportation business.

The Courts below found the first defendant guilty of violation of the Act and theft. The first defendant appealed to the Supreme Court against this verdict. On the other hand, the Courts below found both defendants not guilty of a violation of the Shipping Act, and the prosecutor appealed against that decision.

Held: Both appeals are dismissed. The findings of the lower Courts are confirmed.

The preamble of art 5.1 of the Act stipulates that 'foreign ships may transit harmlessly through the territorial waters of the Republic of Korea within the scope of not impairing the peace, public order, or security of the Republic of Korea'. Paragraph 1 provides:

When a foreign vessel conducts any of the following acts while navigating, it shall be deemed to impair the peace, public order, or security of the Republic of Korea. However, this does not apply to cases where permission, approval, or consent from the relevant authorities has been obtained for the acts of subparagraphs 2 through 5, 11 and 13.

The first defendant argued that it did not fall under the 'passage of foreign ships' provision, and that its activities therefore did not constitute an 'investigation or survey' under art 5.2.11 of the Act. However, art 5.2 of the Act covers instances where a foreign vessel is navigating for the purpose of crossing the territorial sea; for the purpose of advancing towards or departing from domestic waters; or making a call to a marina or port facility. It should be interpreted as meaning any case of navigating across the territorial sea.

In addition, 'investigation' in art 5.2.11 of the Act means 'any investigation targeting the seabed, subsoil, upper water area, and adjacent atmosphere in order to understand and reveal the natural environment and condition of maritime activities', and is not limited to cases that substantially harm peace, public order, or security in the Republic of Korea for the following reasons:

a) The right to innocent passage in the territorial sea of a foreign ship entails restrictions on the sovereignty of the coastal State. It includes the meaning of not infringing sovereign rights.

b) In the case of 'fishing' in art 5.2.10 of the Act, unauthorised fishing is a violation of the right to fish, which is an important content of sovereignty, even if unauthorised fishing is non-hazardous, and does not impair the peace, public order, or security of the coastal State in itself.

c) Article 21.1.g of UNCLOS stipulates that coastal States can enact laws and regulations on 'marine scientific research and hydrographic surveys' in relation to innocent passage, and art 245 of UNCLOS stipulates that scientific investigations must be carried out with the express consent of the coastal State, which means that investigation activities in the territorial sea without the express consent of the coastal State are not permitted, regardless of whether or not they substantially harm peace, public order, or security.

d) In addition, if a foreign vessel collects information on the natural environment and condition of the sea through investigation activities in territorial waters, there is a risk that such information will be used to harm the peace and safety of the coastal State in the future. It cannot be concluded that the peace, public order, or security of the Republic of Korea will not be harmed.

It is clear that the first defendant investigated the seabed using a fish finder installed on a foreign ship to find the location of the sunken ship in the waters of Mengolsudo, Jindo. This falls under art 5.2.11 of the Act. Therefore, the lower Courts' conclusions were correct.