Acadian hermit crab 
Achaeus spinosus 
Adinda lamellata 
Aggtelek Blind Sideswimmer 
Alcyonohippolyte dossena 
Aliaporcellana spongicola 
Allogalathea babai 
Amazon freshwater crab 
Amazon River Prawn 
Ambiguous Crayfish 
American lobster 
Anchor Coral Shrimp 
Ancylomenes longicarpus 
Ancylomenes pedersoni 
Ancylomenes sarasvati 
Ancylomenes tenuirostris 
Anemone hermit crab 
Anker's whip coral shrimp 
Ant Woodlouse 
Arachnothelphusa merarapensis 
Arcitalitrus dorrieni 
Armadillidium granulatum 
Arrow Crab 
Arrowhead crab