1. Swimming: Swimming is a low-impact exercise, which helps to improve children's cardiopulmonary function, muscle strength and coordination.

2. Yoga: Yoga can help children improve their flexibility, balance and concentration, and at the same time cultivate their self-awareness and self-confidence.

3. Dance: Dance can help children develop their whole body muscle strength, coordination and sense of rhythm, and also cultivate their artistic accomplishment and teamwork spirit.

4. Gymnastics: Gymnastics can exercise children's flexibility, strength and sense of balance, and also cultivate children's self-discipline and perseverance.

5. Hiking or running: Hiking or running can exercise children's cardiopulmonary function, endurance and coordination, and also cultivate children's environmental awareness and healthy lifestyle.

6. Team sports such as football and basketball: These sports can help children develop team spirit, sense of cooperation and competition, and also exercise their physical fitness.

7. Children's Yoga: This is a kind of yoga course specially designed for children, aiming to help children develop physical and mental balance and improve flexibility and coordination.

8. Children's Wushu: Tai Ji Chuan, Qigong, etc. It can help children improve their coordination, balance and flexibility, and also cultivate their self-discipline and concentration.

9. Children's calisthenics: This is an aerobic exercise combining music and movements, which can help children improve their cardiopulmonary function, muscle strength and coordination.

10. Children's outdoor games: such as hide-and-seek and tug-of-war, can help children exercise and cultivate team spirit and competitive consciousness.

In a word, three-year-old children are suitable for all kinds of sports. The key is to choose suitable sports according to children's interests and physical condition, and ensure the safety during the exercise.