The Lower River Shannon Special Area of Conservation (SAC) incorporates the estuary and is 120 km (75 mi) in length, running from Killaloe to Loop Head.

In 1936, the government of Ireland confirmed that it would develop a 3.1 km2 (1.2 sq mi) site at Rineanna for the country's first transatlantic airport.

By 1945 the existing runways at Shannon were extended to allow transatlantic flights to land, completely bypassing the need for Foynes.

It provides marine services, including pilotage and towage to privately owned facilities at Moneypoint, Tarbert Island and Aughinish.

The maritime history of the estuary is catalogued and on display in exhibits at the Maritime Section of the Foynes Flying Boat Museum[6] The Shannon Estuary is an immensely important asset and one of the most valuable natural resources in Ireland and the Mid-West Region in particular – the fringe lands and the marine area both provide space and location for development activities and opportunities to progress economic, social, and environmental growth within the Region.

[14][15] Though the Shannon estuary the fishing industry is now depleted, though at one time it provided employment for hundreds of men along its length.