Electronic devices that are biodegradable, water soluble and flexible and are fabricated using biodegradable materials are of great importance due to their potential application in biomedical implants, personal healthcare etc. Moreover, despite the swift growth of semiconductor technologies and considering a device’s shell life of two years, the subject of electronic waste (E-waste) disposal has become a major issue. Transient electronics is a rapidly expanding field that solves the issue of E-waste by destroying the device after usage. The device disintegration can be caused by a multitude of triggering events, an example is that the device totally dissolves and/or disintegrates when submerged in water. This technology enables us to utilize electronic devices for a set amount of time before quickly destroying them, lowering E-waste significantly. This review will highlight the recent advancement in water-soluble flexible electronic devices with more focus on functional materials (water insoluble), fabrication strategies and transiency understanding with special importance on areas where these devices exhibit potential application in flexible and wearable electronic devices which includes field effect transistors, photodetectors, memristors and sensors for personal healthcare monitoring.