It is found on sandy or gravelly areas in the East Pacific ranging from California (USA) to Ecuador.

[2] Astropecten armatus is a dorsally flattened starfish, which grows to a diameter of about 17 cm (7 in).

[3] Astropecten armatus is found in the eastern Pacific Ocean on sandy or soft gravel seabeds, often semi-submerged in the sediment.

[2] Off the western coast of Mexico, it is the most abundant starfish on suitable substrates, at all depths between 5 and 115 metres (16 and 377 ft).

It can consume these at the rate of one each day but, when they are less plentiful, it will turn to other food sources and eat sand dollars and sea pansies and scavenge on dead fish.