Salmonella is a human and animal pathogen causing gastro-enteric diseases worldwide. The key feature of Salmonella infection is its entry into intestinal epithelial cells within a Salmonella-Containing Vacuole (SCV). This original compartment is distinct from empty macropinosomes formed around the infection site. A few minutes after its formation, the SCV increases in size through fusions with the surrounding macropinosomes. On the opposite, Salmonella induces the formation of elongated tubules leading to SCV membrane and volume loss. Later, the SCV can mature into a vacuolar pathogen niche, or be ruptured releasing Salmonella in the host cytosol where the bacteria hyper-replicates. Here, we describe how size control of the early SCV is the main contributor to its stability and consequently determines the Salmonella intracellular niche and growth. We identify the SNAREs required for increasing the SCV size through fusions. We show that this fusion promotes the maintenance of the SCV integrity and the establishment of a vacuolar niche