One of the main differences between Yoga and Pilates is that Yoga can be used for improving the flexibility of the body and it will also gradually increase the flexibility of your joints.
Whereas, Pilates focuses on trying to relax muscles which are tense and provide strengthening of the numerous muscles of the body.
Pilates works from the centre of your body outward. Pilates uses toning and strengthening components/exercises to increase joint mobility, build supple and strong body muscles.
Yoga is more about stretching of the tight muscles. Stress relief, meditative approach.
Overall, the biggest difference in Pilates and Yoga is the ultimate goal you want to achieve.
If you’d like to become more flexible, Yoga would be best to try. If you’d instead like to tone up and strengthen muscles in your body, then try Pilates.