• Ranina ranina Frog crab, red
  Asahigani
  
• Raninoides personatus Hime-nokoha-ásahi
  
• Rathkea octopunctata
• Raylilia uenoi Ueno-kobushi
  
• Retropluma denticulata Yúrei-gani
  
• Rhinospinosa demani Kawari-ákeúsu
  
• Rhizostoma pulmo
• Rissoides desmaresti
• Rochinia debilis Fukure-tsunogani
  
• Rochinia pulchra Hari-tsunogani
  
• Rochinia sagamiensis Sagami-mogani
  
• Rosacea cymbiformis
• Rosacea plicata
• Rossia macrosoma
• Rossia palpebrosa
• Ryukyum yaeyamense Yaeyama-yamagani
  
• Sabinea sarsii
• Sabinea septemcarinata
• Sagitta elegans
• Sagitta enflata
• Sagitta friderici
• Sagitta hexaptera
• Sagitta lyra
• Sagitta maxima
• Sagitta minima
• Sagitta serratodentata
• Sagitta setosa
• Sagitta tasmanica
• Sakaila imperialis Osachila-gani
  
• Sakaila japonica Yamato-ósachira
  
• Sakaina asiatica Mamegani-damashi
  
• Sakaina incisa Yahazu-mamegani-damashi
  
• Sakaina japonica Nihon-mamegani-damashi
  
• Sakaina koreensis Kankoku-mamegani-damashi
  
• Sakaina yokoyai Yokoya-mamegani-damashi
  
• Salpa fusiformis
• Sargassocarcinus sublimis Konoha-modoki
  
• Sarmatium striaticarpus Mizote-ashihara-gani
  
• Sarsia lovenii
• Sarsia occulta
• Sarsia piriforma
• Sarsia striata
• Sarsia tubulosa
• Sarsiella capsula
• Schistomysis kervillei
• Schistomysis ornata
• Schistomysis parkeri
• Schistomysis spiritus
• Schizophroida hilensis Manazuru-nokogiri-gani
  
• Schizophroida simodaensis Shimoda-nokogiri-gani