Whereas outdoor pickleball is typically played on a tennis court marked out for pickleball, or a custom-made pickleball court, when people talk about “indoor pickleball” they are usually referring to pickleball that is played on a court that is marked out on an indoor wooden, gymnasium floor.
Outdoor pickleball balls normally have smaller holes than their indoor counterparts. Outdoor pickleball balls are also significantly harder than indoor models.
The reason outdoor pickleball balls are designed with smaller holes and more weight is because, unlike indoor pickleball balls, they have to withstand the wind and outdoor elements. The smaller holes & harder construction found with outdoor pickleball balls prevent the wind from influencing the ball’s trajectory as much as it otherwise would.