The captain of a fishing vessel flying the national flag, with a commercial industrial fishing permit, must be a Uruguayan citizen.
"Article 4
Commercial fishing and hunting activities that are carried out in inland waters and the Territorial Sea in an area twelve miles in length, measured from the base lines, are reserved exclusively for national flag vessels, duly authorized, without prejudice to the provisions of the international agreements entered into by the Republic on the basis of reciprocity.
Article 5
Beyond the twelve mile zone mentioned in the previous article, foreign-flagged fishing vessels may only exploit the living resources existing between twelve and two hundred nautical miles, by authorization of the Executive Branch, granted by in accordance with this law and its regulations or in accordance with what the international agreements entered into by the Republic shall provide for this.
The aforementioned vessels must in all cases be subject to to the measures for the preservation of living resources that are adopted in the area and control that is established.
Article 6
Authorizations for the exercise of aquatic fishing and hunting of a commercial or scientific nature will be temporary and renewable and will indicate the water sector for which they will be valid and the circumstances in which they will be suspended or cancelled.
Scientific fishing may be carried out for research or teaching purposes, by national or foreign institutions, or by duly authorized individuals. For the fulfillment of specific programs, no type of limitations will apply, except those that may be stated in the respective authorization.
Sport fishing will not require special authorization, being subject to current regulations.
Article 7
Aquatic living resources of a renewable nature, which have access by fishermen or vessels of national registration and by foreign vessels duly authorised in accordance with this law and its regulations shall be subject to rational exploitation, in order to obtain constant optimal performance from them.
[...]
Article 10
The ships referred to in article 8 are all those that, under a foreign flag, are dedicated to the exploitation of the living resources of the sea in the form of fishing, hunting or extraction, and those that are used as factories or meat processing plants for products obtained by the former.
These refrigerated vessels or factories will pay double the fees established in article 9 for registration and fishing permits.
The Executive Branch, by founded decree, may extend the benefits agreed upon by article 38 of this law to national flag vessels, to foreign flag vessels operated by Uruguayan companies as long as they enter into agreements with the Executive Branch for the replacement of these vessels by national flag vessels within a period of five years of their arrival in the country.
The Executive Branch may enter into these agreements whenever the volume and material and moral solvency of the companies justify it, and may demand additional guarantees when it deems necessary, as well as give preference to those that act in association with the State.
[...]
Article 23
 The Ministry of Industry and Commerce, due to the provisions of article 15, may establish the limitation of the number of vessels dedicated to commercial fishing.
Permits for foreign vessels, provided for in article 8, will be agreed upon by the Executive Branch, and must be registered in a special Registry kept by the SOYP.
 Vessels dedicated to maritime fishing and hunting destined for national fishing companies whose product is landed in Uruguayan ports must have a national registration, except for the authorizations that the Executive Branch, following a report from the SOYP, agrees on a term and revocable basis by virtue of the fishing specialty to be carried out; In such cases, provisions must be made for their replacement, under terms to be established, by national vessels. The Executive Branch, for justified reasons, may exempt foreign fishing vessels from paying the registration fee and fishing permit provided for in Article 8.
 Likewise, in order to authorize the development of this activity by national or foreign flagged vessels, it may require that the fishing product be totally or partially industrialized in the country.
[...]
Article 27
The fishing vessels with national registration, holding commercial industrial fishing permits in categories A and B, shall be commanded by Uruguayan citizen captains or skippers, whether natural or legal persons. Additionally, their crew must consist of no less than 70% (seventy percent) Uruguayan citizens, whether natural or legal persons, or residents in the country in any of its categories.
In the case of categories C and D, they shall be commanded by Uruguayan citizen captains or skippers, whether natural or legal persons, and their crew must also consist of no less than 50% (fifty percent) Uruguayan citizens, whether natural or legal persons, or residents in the country in any of its categories.
In both cases, the percentage may be altered in compliance with international agreements.
Foreign-flagged fishing vessels, holding commercial industrial fishing permits in categories A, B, C, or D, or research fishing permits, must have a crew consisting of no less than 10% (ten percent) Uruguayan citizens, whether natural or legal persons.
In the case of exploratory or new fisheries employing technologies not previously used in traditional or seasonal Uruguayan fisheries, the Executive Branch may modify the percentages referred to in the preceding paragraphs, following consultation with representative organizations of workers, shipowners, entrepreneurs, and captains.
The Executive Branch shall regulate incentives or exemptions for fishing vessels with a crew comprising equal to or more than 75% (seventy-five percent) Uruguayan citizens, whether natural or legal persons, in the case of permits in categories C and D, and which process and transform onshore in Uruguayan facilities the merchandise resulting from fishing, prior to its sale to the market.[...]" (Law No. 13833 "Fishing Law. Fishing Permits" (29 December 1969), last amended by Law No. 19.996 of 3 November 2021, Article 27 [google translation])
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Previously up to 2020
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"Article 27
Fishing vessels with national registration, with a commercial industrial fishing permit in categories A and B, will be commanded by captains or patrons, natural or legal Uruguayan citizens, and their crew must also be made up of no less than 90% (ninety percent) Uruguayan natural or legal citizens.
In the case of categories C and D, they will be commanded by captains or patrons, Uruguayan natural or legal citizens, and their crew must also be made up of no less than 50% (fifty percent) of Uruguayan natural or legal citizens.
In both cases, the percentage may be altered in compliance with international agreements.
In the case of exploratory or new fisheries, in which technologies not previously used in traditional Uruguayan or zafrales fisheries are applied, the Executive Power may, after consulting representative organizations of workers, shipowners, businessmen, and captains, modify these percentages .
The Executive Power will regulate the incentives or exemptions to rates established in article 34 of Law No. 19,175, of 20 December 2013, for fishing vessels that:
A) They have a percentage equal to or greater than 75% (seventy-five percent) of the crew of Uruguayan natural or legal citizens in the case of category C and D permits.
B) Process and transform the merchandise resulting from fishing in Uruguayan facilities on land, prior to its sale to the market.[...]" (Law No. 13833 "Fishing Law. Fishing Permits" (29 December 1969), last amended by Law No. 19.924 of 18 December 2020, Article 27 [google translation])
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Previously up to 2019
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"Article 27.- Fishing vessels of national registration shall be commanded by captains or skippers who are natural or legal Uruguayan citizens, and their crew shall be composed of no less than ninety per cent (90%) of natural or legal Uruguayan citizens. This percentage may be altered in compliance with international agreements. 
Without prejudice to the provisions of the previous paragraph, the crew of nationally registered fishing vessels operating exclusively in international waters must be made up of at least 70% (seventy per cent) of natural or legal Uruguayan citizens.
In the case of exploratory or new fisheries, or those in which technologies not previously used in traditional Uruguayan fisheries, or in the case of fishing in the fishing grounds, the Executive Power may, after consulting shipowners, employers, captains and workers' representative organisations, modify these percentages"[...]. (Law No. 13833 "Fishing Law. Fishing Permits" (29 December 1969), last amended by Law No. 18.498 of 30 June 2009, Article 27 [google translation]
Law No. 13833 "Fishing Law. Fishing Permits" (29 December 1969), last amended by Law No. 19.996 of 3 November 2021, Article 27 [google translation]
Law No. 13833 "Fishing Law. Fishing Permits" (29 December 1969), last amended by Law No. 19.924 of 18 December 2020, Article 27
Law No. 13833 "Fishing Law. Fishing Permits" (29 December 1969), last amended by Law No. 18.498 of 30 June 2009, Article 27 [google translation]
[<a href="https://www.impo.com.uy/bases/leyes/13833-1969">Law</a>],[<a href="https://www.impo.com.uy/bases/leyes/13833-1969">Law</a>],[<a href="https://www.impo.com.uy/bases/leyes-originales/18498-2009/1">Law</a>]