For the most part, it’s acceptable to wear a paintball mask for airsoft because it’s designed to handle the greater impact of paintballs compared to small airsoft pellets. Paintball masks are also more flexible and less liable to fog up. As a matter of fact, you’ll commonly see new airsoft players using paintball masks at first, but they usually upgrade to a purpose-built airsoft helmet. They do this because many airsoft arenas have strict rules, and some only permit certain styles of safety equipment, such as full-face masks. Also, the vents in paintball masks are designed to protect against larger projectiles and might allow smaller pellets to pass through them.