Researchers often ask whether there are particular times of day when more participants are available on Prolific. While participant activity varies by region, there are some clear patterns that can help you decide when to launch your study.
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The graphs below show the average number of study submissions started per hour across different participant regions, as well as overall platform activity.

Participant activity starts to increase during the morning, continues to grow throughout the afternoon, and typically peaks in the late afternoon and early evening.

Compared with participants in the UK and Europe, activity remains higher later into the evening. Longer studies (30+ minutes) tend to receive particularly strong participation during these peak afternoon and evening hours.

Key takeaway: If you're targeting participants in the US or Canada, you'll generally find the largest active participant pool from midday through the early evening.

Activity is generally lower during the early morning, increases steadily throughout the day, and reaches its highest levels during the afternoon and early evening.

For longer studies, participation rises noticeably during the mid-to-late afternoon and remains relatively strong into the evening. Shorter studies show a more even distribution of activity throughout the day.

Key takeaway: If you're targeting participants in the UK or Europe, afternoon and early evening hours (GMT/BST) typically offer the largest active participant pool.

Across all regions, participant activity is generally lowest overnight and increases throughout the day. Activity tends to be highest during US daytime and early evening hours, when participant populations from multiple regions overlap.

Longer studies also tend to see more study starts during these peak periods. Activity gradually declines later in the day as fewer participants are online.

The graphs show the number of submissions started per hour, which depends on there being studies available for participants to take.

Because many studies fill quickly and are often launched during standard working hours, lower activity at certain times may reflect a lack of available studies rather than a lack of willing participants. For example, more participants may be available to take studies late in the evening if studies were still open.

Study starts are generally lower on weekends than on weekdays. However, as with time-of-day trends, this may be influenced by fewer studies being available rather than reduced participant interest.

If your goal is to maximise visibility and recruitment speed, consider launching your study during the afternoon or early evening in the time zone of your target participant population. However, high-quality responses can be collected at any time, and most studies on Prolific fill quickly regardless of launch time.