The best time to post on Instagram on Monday is generally between 9:00 AM and 11:00 AM, when users are active after starting their workday. Engagement is typically higher in the morning as people check their phones for updates. However, your optimal time can vary based on your audience’s location, age, and habits. Use Instagram Insights to analyze when your followers are most active. Testing different times and tracking performance can help you find your personal best posting window.