Modern mobile phone applications offer much support to various age group users. Unfortunately, there are still issues with the interfaces in terms of its learn ability. Many users find it hard to learn and use the modern mobile phone application interfaces. Despite a lot of ongoing research examining the mobile phone applications interfaces learnability issues, very little research has explored on the difficulty faced by the users when interacting with graphical icons, the most important element of an interface. This paper presents an exploratory study to identify which icons characteristics support the initial icon usability for various age group users. Twenty five (25) test participants from two different age groups took part in the study. The first group consists of 12 younger adults (age 20-40) and the second consists of 13 older adults (age 50+). From the study findings, both age group users stated that there are issues with the existing mobile phone applications interfaces. The study reveals that specific icon characteristics - complexity (i.e. how difficult is icon to identify and interpret), familiarity (how familiar are users with the icon) and semantic distance could improve icon learnability. This led to a discussion on how the findings could help mobile phone application interface developers to develop mobile phone icons that best suits to the requirements of various age group users. © 2013 IEEE.