Whether you call it a stability ball, a Swiss ball, a yoga ball, or a birthing ball, a quality exercise ball should support the weight of your moving body, retain air, and deflate slowly if punctured. After spending 30 hours doing research, plus nearly two hours inflating seven top contenders from the more than 80 models we considered, we’ve found that the TheraBand Pro Series SCP Exercise Ball is the best exercise ball. It’s made of sturdy yet flexible plastic that, when properly inflated, tied for the most-supportive seat among all the models we tested, and its plug provided the tightest seal.
Our pick

TheraBand Pro Series SCP Exercise Ball
This pro-recommended ball tied for the sturdiest seat and retained air the best of everything we tested, and comes in sizes suitable for people 4′8″ to 6′5″ and even taller.
Buying Options
*At the time of publishing, the price was $46.
The TheraBand Pro Series SCP Exercise Ball required the most time and energy to inflate of all the balls we tested, but the effort paid off with an extra-supportive seat. It’s made of a thick and weighty PVC that’s slick enough to facilitate movement but sticky enough to provide a safety-enhancing grip. And, compared with some other models we tested (all of which come in sizes for people 4′8″ to 6′5″ tall), it’s available in an additional, larger size, making it suitable for taller or longer-legged users.
Runner-up

If the TheraBand Pro Series is unavailable, we recommend the Power Systems VersaBall Stability Ball, which tied for the sturdiest, most-supportive seat among all the balls we tested. In our testing, this ball required the second-most time and effort to inflate, which speaks to its quality. It too is made of a thick and weighty PVC that strikes the right balance between slick and sticky, and it also comes in sizes that accommodate people from 4′8″ to 6′5″ and even taller.
Budget pick

GoFit Pro Stability Ball
This ball comes with everything you need to start using it, although we recommend an alternative inflation tool.
Buying Options
*At the time of publishing, the price was $25.
If you don’t have access to an inflation tool and would appreciate having exercise illustrations printed on the ball, we recommend the GoFit Pro Stability Ball as a budget option. Compared with all the other models we tested, the GoFit Pro Stability Ball is made of the weightiest PVC, but it has thinner walls than the TheraBand Pro Series and Power Systems VersaBall making it a slightly less supportive seat. Unlike our other picks and runner-up, this less-expensive model comes packaged with a hand/foot pump, which you may find frustrating but nevertheless can be used to fully inflate the ball if you don’t have access to another tool, such as a bike pump.