Acoustic characteristics of a subsurface, cold core eddy observed in the Bay of Bengal during southwest monsoon period is presented based on CTD (Conductivity Temperature Depth) data from 42 stations. The effect of the eddy is to reduce the ambient sound speed by about 10 m.s sup(-1). Under the influence of the eddy, depth of SOFAR channel axis remains constant (1600 m) which otherwise should have shown a deepening in this region. Simulated ray arrival structure depicts the typical characteristics of weak acoustic wave guide in the Bay of Bengal - the early arrival cluster of near axial flat angle rays, later arrivals of deep turning rays followed by the weak latest arrivals of near-surface turning rays. The arrivals of the acoustic rays are delayed by about 100-200 ms under the influence of eddy. The intensity computations show that when the ray passes through the eddy, it suffers an additional loss of 20-25 dB. From the simulated travel time delays, the eddy profile is reconstructed through generalised inverse, based on singular value decomposition technique. The numerical experiment shows that 18 eigen rays with 9 layers enable reconstruction of the eddy profile adequately using 9 eigen modes