There are 75 species of echinoderm (phylum Echinodermata) recorded in Ireland.^[1][2][3][4]

Class Asteroidea (sea stars)

Order Forcipulatida

Family Asteriidae

• Asterias rubens (common sea star)
• Leptasterias muelleri (northern sea star)
• Marthasterias glacialis (spiny sea star)
• Stichastrella rosea

Order Paxillosida

Family Astropectinidae

• Astropecten irregularis (sand sea star)

Family Luidiidae

• Luidia ciliaris (seven-armed sea star)
• Luidia sarsi

Order Spinulosida

Family Echinasteridae

• Henricia oculata (bloody Henry starfish)
• Henricia sanguinolenta (northern henricia, bloody henry)

Order Valvatida

Family Asterinidae

• Anseropoda placenta
• Asterina gibbosa (starlet cushion star)
• Asterina phylactica

Family Poraniidae

• Porania pulvillus

Order Velatida

Family Solasteridae

• Crossaster papposus (common sunstar)
• Solaster endeca (purple sunstar, northern sunstar, smooth sun star)

Class Crinoidea (sea lilies, feather stars)

Order Comatulida (feather stars)

Family Antedonidae

• Antedon bifida (rosy feather star)
• Antedon petasus
• Leptometra celtica

Class Echinoidea (sea urchins)

Order Camarodonta

Family Parechinidae

• Paracentrotus lividus (purple sea urchin)
• Psammechinus miliaris (green sea urchin / shore sea urchin)

Order Clypeasteroida (sand dollars)

Family Echinocyamidae

• Echinocyamus pusillus (pea urchin)

Order Echinoida

Family Echinidae

• Echinus esculentus (European edible sea urchin)

Order Spatangoida (heart urchins)

Family Loveniidae

• Echinocardium cordatum (sea potato)
• Echinocardium flavescens (yellow sea potato)
• Echinocardium pennatifidum

Class Holothuroidea (sea cucumbers)

Order Apodida

Family Synaptidae

• Labidoplax digitata
• Leptosynapta bergensis
• Leptosynapta inhaerens

Order Holothuriida

Family Holothuriidae

• Holothuria forskali (black sea cucumber / cotton-spinner)

Order Dendrochirotida

Family Cucumariidae

• Aslia lefevrei
• Cucumaria frondosa (orange-footed sea cucumber)
• Leptopentacta elongata
• Ocnus lacteus
• Ocnus planci
• Paracucumaria hyndmani (Hyndman's sea apple)
• Pawsonia saxicola (sea gherkin)
• Thyonidium drummondii

Family Phyllophoridae

• Neopentadactyla mixta
• Thyone fusus
• Thyone roscovita

Class Ophiuroidea (brittle stars)

Order Ophiurida

Family Amphiuridae (long-armed burrowing brittle stars)

• Amphipholis squamata (brooding snake star, dwarf brittle star)
• Amphiura brachiata
• Amphiura chiajei
• Amphiura filiformis
• Amphiura securigera

Family Ophiactidae

• Ophiactis balli
• Ophiopholis aculeata (crevice brittle star, daisy brittle star)

Family Ophiocomidae

• Ophiocomina nigra (black brittle star / black serpent star)
• Ophiopsila annulosa

Family Ophiothricidae

• Ophiothrix fragilis (common brittle star)

Family Ophiuridae

• Ophiocten affinis
• Ophiura albida (serpent’s table brittle star)
• Ophiura ophiura (serpent star)