Only Colombian nationals can own a commercial vessel registered under the Colombian flag. Inland transport services can only be provided by authorised Colombian shipping companies through Colombian-flagged vessels. 
"ARTICLE 1437. NATIONALITY OF VESSELS REGISTERED IN COLOMBIA.
Every ship registered in Colombia is of Colombian nationality and, therefore, must fly the Colombian flag.
[...]
ARTICLE 1458. OWNERS OF THE COMMERCIAL VESSEL REGISTERED IN COLOMBIA.
Only Colombian nationals can own a commercial vessel registered in Colombia.[...]" (Decree no. 410 issuing the Commercial Code (27 March 1971), last amended by Law no. 2069 of 2020, Articles 1437 and 1458 [google translation])
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"ARTICLE 23. In order for a vessel to navigate through the nation's waterways, it must have a Colombian flag and be registered with the Ministry of Transportation through river inspections, and be provided with the respective navigation patent.[...]" (LAW 1242 OF 2008 (August 5): National Code of Navigation and River Port Activities and other provisions [google translate])
Decree no. 410 issuing the Commercial Code (27 March 1971), last amended by Law no. 2069 of 2020, Articles 1437 and 1458
LAW 1242 OF 2008 (August 5): National Code of Navigation and River Port Activities and other provisions, Article 23
[<a href="https://www.alcaldiabogota.gov.co/sisjur/normas/Norma1.jsp?i=41102">Code</a>],[<a href="http://www.secretariasenado.gov.co/senado/basedoc/ley_1242_2008.html">Code</a>]