In recent years, microneedle-based (MN-based) diabetes devices have advanced significantly for wearable biosensors and continuous glucose monitoring. These devices utilize interstitial fluid (ISF) as a biomarker source to diagnose diabetes. While early work focused on ISF extraction, current research trends are geared towards developing in vivo glucose sensors with optical or electrochemical instrumentation. This article highlights the essential characteristics of sensing mechanisms, rational design, sensing properties, and applications of MN-based sensors. It also discusses the challenges and prospects of optical and electrochemical MN-based device platforms for the fabrication of wearable biosensors and their application potential in the future.