A foldable and portable shelter includes a base member and an upper member combined with the base member. The base member includes a bottom wall panel, a rear wall panel, and a front wall panel. Each of the rear wall panel and the front wall panel has a periphery provided with multiple first reinforcing ribs each having an arcuate concave surface. The upper member includes a top wall panel and two opposed side wall panels. Each of the top wall panel and the side wall panels has a periphery provided with multiple second reinforcing ribs each having an arcuate concave surface. Each of the second reinforcing ribs overlaps the respective first reinforcing rib so that the second reinforcing ribs cooperate with the first reinforcing ribs to reinforce the strength of the upper member and the base member.