As with other valviferan isopods, the uropods are ventral to the pleotelson, forming a valvelike covering over the pleopods (photo). Idotea ochotensis has a body which is definitely dorsoventrally flattened and with 7 free pereonites. The lateral margins of the cephalon do not have a deep incision. The eyes are lateral. The pleon has 2 free pleonites plus a pleotelson (which has a pair of lateral incisions showing the margin of a third partly free pleonite). The pleon has a definite point on the posteromedian margin. The lataral margins of the pleon, and the posterior margins of the pleon on either side of the posteromedian point are often concave. The palp of the maxilliped has only 4 articles. Length to 4.2 cm, width to 1.6 cm.