The sensitivity of marine crustaceans to anthropogenic CO2 emissions and the associated acidification of the oceans may be less than that of other, especially lower, invertebrates. However, effects on critical transition phases or carry-over effects between life stages have not been comprehensively explored. Here we report the impact of elevated partial pressure of CO2 (pCO2) values (3100 μatm) in seawater on Hyas araneus during the last 2 wk of their embryonic development (pre-hatching phase) and during development while in the consecutive zoea I and zoea II larval stages (post-hatching phase). We measured oxygen consumption, dry weight, developmental time and mortality in zoea I to assess changes in performance. Feeding rates and survival under starvation were investigated at different temperatures to detect differences in thermal sensitivities of zoea I and zoea II larvae depending on pre-hatch history. When embryos were preexposed to elevated pCO2 during maternal care, mortality increased about 60% under continued CO2 exposure during the zoea I phase. The larvae that moulted into zoea II displayed a developmental delay by about 20 d compared to larvae exposed to control pCO2 during embryonic and zoeal phases. Elevated pCO2 caused a reduction in zoea I dry weight and feeding rates, while survival of the starved larvae was not affected by seawater CO 2 concentration. In conclusion, CO2 effects on egg masses under maternal care carried over to the first larval stages of crustaceans and reduced their survival and development to levels below those previously reported in studies exclusively focussing on acute pCO2 effects on the larval stages. © Inter-Research 2014.