Field observations for research of oceanographic characteristics in waters adjacent to fish farm on land and water quality at area where water is supplied to fish farm and area where water is discharged from fish farm are carried out in coastal waters of Pyoson located in the southeastern region of Jeju Island in March, May, August and November of 2000. Semidiurnal tides to the northeast and southwest dominate. The mean velocities of current around neap tides and spring tides are 8.52cmㆍs$^{-1}$, 28.63cmㆍs$^{-1}$, respectively. The difference of temperature between area where water is supplied to fish farm and area where water is discharged from fish farm is about 0.6$^{circ}C$. Seasonal variation range for temperature and salinity is 13.5$^{circ}C$ and 3.5psu, individually. Concentrations of nitrate(NO$_3$$^{-}$), phosphate(PO$_4$$^{3-}$ ), silicate(SiO$_2$) and COD(chemical oxygen demand) are high in autumn. Particularly, concentrations of nitrate and COD in winter and spring at station where water is supplied to fish farm are higher than these at station where water is dischared from fish farm. However, concentration of phosphate and silicate at station where is supplied to fish farm in spring, summer and autumn is higher than that at station where water is dischared from fish farm. Water quality in the study area is grade 1 and this level is kept up in the whole year.