• Hymenodora glacialis
• Hyperia galba
• Hyperia medusarum
• Hyperoche medusarum
• Hypocolpus abbotti Kebuka-kubomi-ohgigani
  
• Hypocolpus haani Kubomi-ohgigani
  
• Hypocolpus kurodai Kerama-kubomi-ohgigani
  
• Hypothalassia armata Champagne crab
  Matsuba-gani
  
• Idotea balthica
• Idotea chelipes
• Idotea emarginata
• Idotea granulosa
• Idotea linearis
• Idotea metallica
• Idotea neglecta
• Idotea pelagica
• Ihlea punctata
• Ihleus lanatus Hime-tamakobushi
  
• Ihlopsis tirardi Newcaledonia-homora
  
• Illex coindetti
• Ilyograpsus nodulosus Sakishima-íwagani
  
• Ilyograpsus paludicola Thai-íwagani
  
• Ilyoplax delsmani White semaphore crab
  Jakarta-chigogani
  
• Ilyoplax dentimerosus Shen-chigogani
  
• Ilyoplax deschampsi Haragukure-chigogani
  
• Ilyoplax formosensis Taiwan-chigogani
  
• Ilyoplax integer Minami-chigogani
  
• Ilyoplax ningpoensis Chugoku-chigogani
  
• Ilyoplax pingi Pingi-chigogani
  
• Ilyoplax pusillus Chigogani
  
• Ilyoplax serratus Xiamen-chigogani
  
• Ilyoplax stapletoni Bangladesh-chigogani
  
• Ilyoplax tansuiensis Tansui-chigogani
  
• Intesius pilosus Wagu-énkougani
  
• Iphiculus spongiosus Konoha-kobushi
  
• Iphinoe serrata
• Iphinoe trispinosa
• Ixa cylindrus Kabuto-kobushi
  
• Ixa inermis Leach-kabuto-kobushi
  
• Ixa pulcherrima
• Izanami curtispina Hime-kinsengani
  
• Janthina exigua
• Janthina janthina
• Jonas choprai Chopra-higegani
  
• Jonas distincta Higegani
  
• Jonas formosae Taiwan-higegani
  
• Jonesius triunguiculatus Maldivia-gani
  
• Ketamia handokoi Tavares-mameheike
  
• Kraussia rugulosa Shiwa-goishi-gani
  
• Kraussia truncatifrons Futakobu-goishi-gani