The appeal of seaside bowling lies in its advantages bare feet allowed, the alley's free, and there's an unlimited supply of pins.
Make 10 pins by filling a cup with moist sand (add water if the sand is too dry to hold a shape). Carefully turn the cup over and lift it off. Create the pins in a triangle with one pin in front, two pins in the next row, three in the next and four in the back row.
Draw a line in the sand about 6 or 8 feet from the pins. Take turns standing behind the line and rolling a softball or other small ball toward the pins to knock them over. Each player gets to roll the ball twice.
Count how many pins you knock over, set them up again and keep score in the sand.