In 1970 the company began operating in the maritime sector. Since then, Etermar has participated in Portugal's most demanding marine projects.

In 1985, the company was a pioneer in building the country's first submarine outfalls: Carvoeiro (1989), Baleeira (1989), Sagres (1990), and Espinho (1992). During this period, it also designed and built Portugal's first artificial reefs along the Algarve's coast (1990).

As of 1997, it had carried out various agricultural hydraulic projects. In this sector of irrigated farmland, it designed and implemented innovative projects in Trás-os-Montes and Alqueva, with emphasis on irrigation networks, zoned embankment dams, trapezoidal channels and hydraulic tunnels.

In the late 1990s, the company began building cable cars, with the first being located on Madeira Island: Rocha do Navio Cable Car (1998) and the Funchal Cable Car (2000).

In 2006, the ingredients for the company's internationalisation were gathered: a robust management model, competent technical staff, and a large fleet of marine equipment.

Therefore, in that same year, it won its first international tenders, the submarine outfalls of Tangier and Tetouan in Morocco, and the construction of its first quay in Equatorial Guinea. Then, the company built the Port of Oran and the seawater intake pipelines for the Fouka desalination plant in Algeria.

In 2008, Etermar's revenue abroad had already surpassed the company's turnover in Portugal.

In 2010, the company increased its share capital from 15 to 25 million euros, allowing it to improve the company's financial strength and competitiveness in the international market.

The successes achieved in projects in very different countries and cultures around the globe, such as Algeria, Brazil, Cape Verde, Equatorial Guinea, Malta, Morocco, Dominican Republic or Tunisia, show that the commitment to continuous training, a constant adaptation to the most demanding technical requirements, and the investment in the best equipment available, are crucial factors that make Etermar a company internationally known for its expertise.