From September 30 to November 4, 2018, a member of LIMU, PhD student D.A. Nikolaev visited Raja Ali Haji Maritime University (Universitas Maritim Raja Ali Haji – UMRAH, Tanjung Pinang, Indonesia) and took part in tests of acoustic equipment for monitoring marine organisms conducted by Indonesian scientists. The measurements were carried out in the South China Sea off the coast of Bintan Island. At the Raja Ali Haji Maritime University, Dmitry gave a talk on the application of hydroacoustics in environmental monitoring, and also discussed with his colleagues the possibilities of acoustic methods for assessing pollution of the aquatic environment. A month later, from December 7 to December 18, these studies were continued in Hangzhou, China. Dmitry took part in this second part of the trial, now with colleagues from the Chinese branch of UMRAH. Studies were conducted on hydrology and seabed off the coast of Zhoushan Island in the East China Sea, the results of which Dmitry used to simulate the propagation of acoustic waves in a shallow water with the help of the acoustic-ray program he developed. Dmitry's trips to Indonesia and China were very interesting both scientifically and from the point of view of acquaintance with Asian culture and traditions.