<p>This paper presents the interactions between headland sand bypassing and overpassing at Santinho’s beach, Brazil. Santinho receives sediments from the south (Moçambique) through headland bypassing and supplies sediment to the north (Ingleses) via headland bypassing and overpassing processes. To understand these interactions we: 1) identified if beach rotation process (often associated with bypassing) occurred in the area using CASSIE tool; 2) validated the headland sand bypassing using topography and geophysics data; 3) quantified the annual sediment transport around headlands, as well the transport to the backshore using numerical modelling. The findings identified a decadal beach rotation, sediment bypass, and negative pulses. A decadal sediment pulse entered the system in 2014, with indications of a subsequent pulse emerging. The presence of megaripples at both headlands confirmed sediment transport (bypassing) and its direction. Numerical models suggest that sediment transport around Ponta das Aranhas Headland amounts to 18,500 m³/year, while bypassing at Morro dos Ingleses Headland, about 12,000 m³/year, resulting in approximately 6,500 m³/year of remaining sediment transport to the backshore - aligning closely with the dune morphological evolution data (6,000 - 7,000 m³/year). Therefore, the results indicated that headland bypassing can control the sediment volume available for overpassing and overpassing rates can control the availability of sand for bypassing. Thus, it is evident that headland beaches should not be treated as closed compartments, even when the shoreline is relatively stable. These beaches can be transitional and dynamic environments where sediment can be transported around obstacles, whether through bypassing or overpassing, as seen at Santinho’s beach. This is the first time documentation of both bypassing and overpassing occurring at a single beach.</p>