Rice fields are a globally important habitat for waterbirds. Portugal is one of the main rice producers in Europe, but little is known about how these rizicultures are used by the avifauna. The continental Black-tailed Godwit Limosa l. limosa is likely the most important avian population using Portuguese rice fields during the Winter and here we describe the main rice plantation areas used by these birds, report their international importance and propose some conservation measures for these areas. The plantations around the Tejo, Sado and Mondego lower basins were surveyed for three winters and peak counts reach roughly 45 000 birds each year. We define eleven areas, all around the Tejo and Sado estuaries as most important for this population, almost all holding over 1% of the population at some point during the surveys. Three areas, Paúl do Trejoito, Paúl de Belmonte and Samora Correia harboured, at least once, over 15% of the population during peak counts, and overall the eleven areas harbored over one third of the population each year. Despite this, most of these rice plantations are outside the lSpetial Protection Areas, and some of the most important ones lay at close distance from the proposed site for the new international airport of Lisboa. We propose some management guidelines for this areas, in terms of banning hunting during key periods, and of ideal farming pratices to maximize Black-tailed Godwit habitat availability. We also believe the international importance of these areas for this near-threatened species, as well as the potential risk of colisions, should be taken into serious consideration when deciding the location of the new airport.