Phosphorus (P) is essential for plant growth but is frequently limiting in tropical agroecosystems due to strong sorption and low availability. The adoption of cover crops (CCs) with high P uptake efficiency can enhance P cycling for cash crops, reducing fertilizer use and improving P-use efficiency. This study aimed to assess changes in soil P dynamics after adopting CCs under contrasting P sources in a sandy soil in dryland conditions in Brazil. The experiment was carried out in sandy loam soil over two maize-growing seasons under no-tillage. Treatments consisted of two P sources (single superphosphate - SSP, and rock phosphate - RP) and a control without P (NilP), combined with six summer CC species (sunn hemp, spectabilis, pigeon pea, lablab, jack bean, and pearl millet) plus fallow. P uptake, P offtake, and soil P fractions were determined in both seasons. Cover crops increased PUE under both P sources. Under SSP, PUE increased significantly after lablab cultivation, reaching 58% compared to fallow. Under RP, all CCs promoted a significant increase in PUE, except for spectabilis. Most cover crops reduced system P balance relative to fallow, indicating greater P export by maize harvest. Sunn hemp was the most efficient CCs in P uptake, similar to 36 kg ha-1 of P from the soil on average across both growing seasons (36% higher than the average of other CCs). In the first season, CCs increased the labile P pool under Nil-P at 0-10 cm depth, especially with spectabilis, pigeon pea, sunn hemp, and pearl millet (similar to 38% higher than fallow). However, this pool was depleted in the second season. Under P fertilization, labile and moderately labile P increased substantially, particularly with pearl millet under RP at 0-5 cm. Across seasons, CCs depleted non-labile P at 10-20 cm and accumulated it in the surface depth. Overall, CCs efficiently cycled P and improved maize PUE most consistently under RP, highlighting that CC selection can be used to increase the effectiveness of sparingly soluble P inputs in sandy, low-buffering dryland soils.