It operates passenger, cargo and RORO vessels to various destinations in the Philippines under the brands Montenegro Lines and Marina Ferries.

The first route that the company served is from Batangas City to Abra de Ilog, Occidental Mindoro using the boat MV Malaya.

[1] Over the past 40 years, MSLI provided passenger and commercial marine transportation services (cargo or vehicles) with a fleet of fast ferries and RORO vessels to 13 ports in the Philippines.

In 2010, the company acquired eight additional RORO vessels worth PH₱1 billion from the Development Bank of the Philippines' Maritime Leasing Corporation and other lenders.

[1] Moreover, the company has a controlling stake over RORO Bus Transport Services Inc., a Philippine bus company that transports passengers to different destinations in the Philippines via the Strong Republic Nautical Highway.