The present paper presents aspects of the morphological behavior of Rio das Pacas Beach, situated in the Southeast portion of the Island of Santa Catarina - SC. The methodology adopted consisted in the monitoring of three beaches profiles, every twenty days, during the period of one year. Besides the topographical survey, there were also carried out observation on height and wave periods, wind direction and intensity and current direction. The results indicated a great variation on the profiles throughout the monitored period, especially evidenced in the values of width and sedimentary supply of the beach (highest variations reaching 30m and 40m3/m between two consecutive expeditions), where it was possible to identify seasonal behavior characterized by accretion during the end of spring and summer and erosion in autumn and winter. The erosive periods were of bigger magnitude than the accretion, and in the extremities of the beach, the complete recovery of sediments was not reached during the monitored period. Events of high energy (undertows) that reached the beach revealed capacity to modify the morphology of the beach system, also eroding frontal dunes settled for vegetation and partially destroying anthropic structures – such as walls, poles, props and fences - constructed on the frontal dune and backshore.