Shell weights of planktonic foraminifera species Globigerinoides ruber in the size range of 300–355 mew m were measured from sediment traps in the western and eastern Arabian Sea which represent upwelling and non-upwelling conditions respectively. In the Western Arabian Sea Trap (WAST), G. ruber flux ranged from 33.3 to 437.3 #/m ²/day and shell weights ranged from 6.7 to 14.2 mew g. Whereas, in the Eastern Arabian Sea Trap (EAST), flux ranged from 0.7 to 164.6 #/m ²/day and shell weights ranged from 10.4 to 14.8 mew g. Shell weights of G. ruber versus flux showed significant correlation at both the sites which reveals that shell calcification mainly depends on optimal growth conditions. Though the WAST and EAST location have distinct difference in pCO₂ and sea surface temperature (SST), the shell weights of G. ruber are similar in these two regions which suggest that surface water pCO₂ and SST do not show dominant influence on shell calcification on a seasonal timescale