After studying on the researches done by the Geological Society of Malaysia, the writer found out that there exist extensive submerged regions along the coasts of Peninsular Malaysia which resulted form the displacement of river mouths. To detect the vertical crustal movements by using tidal data, the writer proposed five methods : i. Use of the Yearly MSL without any correction. ii. Use of teh monthly MSL after removing the mean annual variation. iii. Use of teh Monthly MSL corrected for various effects. 1v. Taking the difference of MSL between two tide stations. v. Use of the Monthly MSL after reving the mean annual ariation and the regional mean fluctuation. From the combined data of the tidal observations and precise levelling, the writer has calculated the rate of vertical crustal movements at three places, namely Tanjung Kabong, Port Dickson and Tanjung Keling which showed the rate of subsidence of 2.5, 1.9 and 4.4 mm/year respectively. The writer has proposed theree major methods that can be used to detect the vertical crustal movements in Peninsular Malaysia : i. Tidal observations. ii. Repeated precise levelling survey. iii Tiltmeter observations.