Introduction: The use of digital communication devices among adolescents has shown a significant rise following COVID 19 pandemic. Objective: Determine the behavioural and usage patterns of screen devices among secondary school students in Sri Lanka. Method: A descriptive cross-sectional study was conducted (January-August 2025) in Colombo, Galle, Jaffna, Anuradhapura and Nuwara Eliya districts, using a self-administered questionnaire. Data analyzed with SPSS v25. Results: All 1438 participants regularly used at least one communication device: mobile phones were the most preferred (96.7%) followed by laptops (42.1%), smart-watches (20.8%) and tablets (16.8%). Majority used smartphones (97 .1%) but only 28.4% owned a phone. 58.1% had peak device usage between 6pm-12am, 43.4% spent ≥2 hours with devices. Device usage was for academic work (85.5%) listening to music (75.0%), taking photos (70.6%), watching videos (60.0%), chatting (65.3%), and browsing social media (46.2%). Engagement of devices was to relieve boredom (74.5%), being alone (44.7%). commonly used in the bedroom (34.3%), during meals (32.5%), and while watching television (24.6%). Communication platforms used were WhatsApp (96.5%), Snapchat (34.1%) and Instagram (21.9%). Mean number of calls given and received were 5.07 and 5.73 respectively . 35.5% did software updates within 1-7 days. During sleep 19.5% kept phone closer, 16.1% carried charger/power bank. Three forth of the group attempted to reduce device usage. Conclusions: All participants were regular users of smart devices. Despite significant use for academics, device engagement is largely driven by boredom and solitude. Future efforts should focus on helping students balance academic needs with healthier digital habits.