The busiest days for Instacart are Saturday, Sunday, and Monday. Instacart requires its in-stores shoppers to work at least 8 hours per week during those three days.
When reviewing other blog articles and reviews, most sources agree that Sunday is the busiest day of the week. However, some drivers have the most success with Mondays and Wednesdays.
The busiest day for Instacart will vary by area. But universally slow days seem to be Fridays, Tuesdays, and Thursdays.