We investigated the device characteristics of GaN-based blue vertical light-emitting diodes (VLEDs) with two different package structures (i.e., lead frame with metal/plastic body (MPLF package) and lead frame with metal body (MLF package)) under various measurement conditions. In comparison with the MPLF packaged VLEDs, the MLF packaged VLEDs exhibited relatively lower junction temperature and thermal resistance values due to the better heat dissipation capability, leading to further improved optical, spectral, and thermal device characteristics. Thermal simulations of the VLEDs with two different packages were performed using three-dimensional steady-state device models to theoretically calculate their thermal and mechanical behaviours. The maximum temperatures, internal temperature distributions, and thermomechanical stresses were analysed by a finite element method. (C) 2016 Elsevier Ltd. All rights reserved.