Vineyards incur the highest soil and water losses among all Mediterranean agricultural fields. The state-of-the-art shows that soil erosion in vineyards has been primarily surveyed with topographical methods, soil erosion plots and rainfall simulations, but these techniques do not typically assess temporal changes in soil erosion. When vines are planted they are about 30 cm high × 1 cm diameter without leaves, the root system varies from 2 to over 40 cmdepth, and sometimes the lack of care used during transplanting can result in a field with highly erodible bare soils. This means that the time since vine plantation plays a key role in soil erosion rates, but very little attention has been paid to this by the scientific community. Thus, the main goal of this research was to estimate soil losses and assess soil erosion processes in two paired vineyard plantations of different ages. To achieve this goal, the improved stock unearthing method (ISUM) was applied to vineyards on colluvial parent materials with similar soil properties, topographical characteristics and landmanagements in the Les Alcusses Valley, southwestern Valencia province, Spain. Our findings suggested that the old vineyards showed lower erosion rates (−1.61 Mg ha−1 yr−1) than those that were recently planted (−8.16 Mg ha−1 yr−1). This is because of the damage that the plantation of the vines causes to soil. Tillage after planting (4 times per year) resulted in changes in the inter-rowand rowmorphology, promoting the development of a ridge underneath the vines that disconnected the inter-rows and reduced soil losseswith time. After the second year and until the 25th year after plantation, soil erosionwas approximately 1Mg ha−1 y−1,whichmeans thatmost of the erosion took place during the first two years after the plantation. Soil conservation strategies should be applied immediately after the plantationworks to allow sustainable grape production. That is when soil erosion most needs to be controlled.