# Isla San Marcos (MX SMI)

**UN/LOCODE:** MX SMI  
**Country:** Mexico  
**Water Body:** Gulf of California; North Pacific Ocean  
**Harbor Size:** Very Small  
**Harbor Type:** Open Roadstead  
**GPS:** 27.1833, -112.1000

Worked since the company's founding in 1923, the gypsum deposit on Isla San Marcos in the Gulf of California is the world's second-largest, and its port exists to ship that single mineral. Operated by Compañía Occidental Mexicana (COMSA), the facility is a captive open-roadstead loading point for dry bulk rather than a container or general-cargo terminal. It moves gypsum (calcium sulfate rock) only — more than 100 million tonnes shipped to date — chiefly to the US west coast, Canada, Japan, the Far East and Latin America. There is no routine customs or liner handling for third-party cargo here; the berth serves the mine alone. Being an island, it has no meaningful road or rail hinterland. For containers, breakbulk or general freight, forwarders should look to Santa Rosalía about 17 km away, and to Guaymas and Mazatlán.

## Transit Times & Routes

- [Mexico City → Shanghai](https://www.freight-academy.com/en/transit-time/mexico-city-shanghai)
- [Mexico City → Shenzhen](https://www.freight-academy.com/en/transit-time/mexico-city-shenzhen)
- [Mexico City → Guangzhou](https://www.freight-academy.com/en/transit-time/mexico-city-guangzhou)
- [Mexico City → Hong Kong](https://www.freight-academy.com/en/transit-time/mexico-city-hong-kong)
- [Mexico City → Tokyo](https://www.freight-academy.com/en/transit-time/mexico-city-tokyo)
- [Mexico City → Busan](https://www.freight-academy.com/en/transit-time/mexico-city-busan)

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*Freight Academy — Seaport Profile: [https://www.freight-academy.com/en/information/seaports/isla-san-marcos-port-mx-smi](https://www.freight-academy.com/en/information/seaports/isla-san-marcos-port-mx-smi)*

*Markdown mirror: [https://www.freight-academy.com/api/md/seaports/en/isla-san-marcos-port-mx-smi](https://www.freight-academy.com/api/md/seaports/en/isla-san-marcos-port-mx-smi)*

*LLM-Summary (JSON): https://www.freight-academy.com/api/v1/seaports/isla-san-marcos-port-mx-smi/llm-summary?lang=en*