A quick-dry base layer long sleeve t-shirt is crucial for regulating body temperature and managing moisture on the Camino. Choose a shirt made from high-performance fabrics like merino wool or synthetic blends that wick moisture away from the skin and dry quickly. Look for features such as flat seams to prevent chafing and a snug, comfortable fit that allows for layering. Breathable materials ensure comfort in varying weather conditions, while antimicrobial properties help reduce odors during extended wear.